/************************************************************************** * * Copyright 2009-2010 VMware, Inc. * All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sub license, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice (including the * next paragraph) shall be included in all copies or substantial portions * of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * **************************************************************************/ /** * @file * Helper * * LLVM IR doesn't support all basic arithmetic operations we care about (most * notably min/max and saturated operations), and it is often necessary to * resort machine-specific intrinsics directly. The functions here hide all * these implementation details from the other modules. * * We also do simple expressions simplification here. Reasons are: * - it is very easy given we have all necessary information readily available * - LLVM optimization passes fail to simplify several vector expressions * - We often know value constraints which the optimization passes have no way * of knowing, such as when source arguments are known to be in [0, 1] range. * * @author Jose Fonseca */ #include "util/u_memory.h" #include "util/u_debug.h" #include "util/u_math.h" #include "util/u_string.h" #include "util/u_cpu_detect.h" #include "lp_bld_type.h" #include "lp_bld_const.h" #include "lp_bld_init.h" #include "lp_bld_intr.h" #include "lp_bld_logic.h" #include "lp_bld_pack.h" #include "lp_bld_debug.h" #include "lp_bld_arit.h" #define EXP_POLY_DEGREE 5 #define LOG_POLY_DEGREE 5 /** * Generate min(a, b) * No checks for special case values of a or b = 1 or 0 are done. */ static LLVMValueRef lp_build_min_simple(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef b) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; const char *intrinsic = NULL; LLVMValueRef cond; assert(lp_check_value(type, a)); assert(lp_check_value(type, b)); /* TODO: optimize the constant case */ if(type.width * type.length == 128) { if(type.floating) { if(type.width == 32 && util_cpu_caps.has_sse) intrinsic = "llvm.x86.sse.min.ps"; if(type.width == 64 && util_cpu_caps.has_sse2) intrinsic = "llvm.x86.sse2.min.pd"; } else { if(type.width == 8 && !type.sign && util_cpu_caps.has_sse2) intrinsic = "llvm.x86.sse2.pminu.b"; if(type.width == 8 && type.sign && util_cpu_caps.has_sse4_1) intrinsic = "llvm.x86.sse41.pminsb"; if(type.width == 16 && !type.sign && util_cpu_caps.has_sse4_1) intrinsic = "llvm.x86.sse41.pminuw"; if(type.width == 16 && type.sign && util_cpu_caps.has_sse2) intrinsic = "llvm.x86.sse2.pmins.w"; if(type.width == 32 && !type.sign && util_cpu_caps.has_sse4_1) intrinsic = "llvm.x86.sse41.pminud"; if(type.width == 32 && type.sign && util_cpu_caps.has_sse4_1) intrinsic = "llvm.x86.sse41.pminsd"; } } if(intrinsic) return lp_build_intrinsic_binary(builder, intrinsic, lp_build_vec_type(bld->gallivm, bld->type), a, b); cond = lp_build_cmp(bld, PIPE_FUNC_LESS, a, b); return lp_build_select(bld, cond, a, b); } /** * Generate max(a, b) * No checks for special case values of a or b = 1 or 0 are done. */ static LLVMValueRef lp_build_max_simple(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef b) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; const char *intrinsic = NULL; LLVMValueRef cond; assert(lp_check_value(type, a)); assert(lp_check_value(type, b)); /* TODO: optimize the constant case */ if(type.width * type.length == 128) { if(type.floating) { if(type.width == 32 && util_cpu_caps.has_sse) intrinsic = "llvm.x86.sse.max.ps"; if(type.width == 64 && util_cpu_caps.has_sse2) intrinsic = "llvm.x86.sse2.max.pd"; } else { if(type.width == 8 && !type.sign && util_cpu_caps.has_sse2) intrinsic = "llvm.x86.sse2.pmaxu.b"; if(type.width == 8 && type.sign && util_cpu_caps.has_sse4_1) intrinsic = "llvm.x86.sse41.pmaxsb"; if(type.width == 16 && !type.sign && util_cpu_caps.has_sse4_1) intrinsic = "llvm.x86.sse41.pmaxuw"; if(type.width == 16 && type.sign && util_cpu_caps.has_sse2) intrinsic = "llvm.x86.sse2.pmaxs.w"; if(type.width == 32 && !type.sign && util_cpu_caps.has_sse4_1) intrinsic = "llvm.x86.sse41.pmaxud"; if(type.width == 32 && type.sign && util_cpu_caps.has_sse4_1) intrinsic = "llvm.x86.sse41.pmaxsd"; } } if(intrinsic) return lp_build_intrinsic_binary(builder, intrinsic, lp_build_vec_type(bld->gallivm, bld->type), a, b); cond = lp_build_cmp(bld, PIPE_FUNC_GREATER, a, b); return lp_build_select(bld, cond, a, b); } /** * Generate 1 - a, or ~a depending on bld->type. */ LLVMValueRef lp_build_comp(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; assert(lp_check_value(type, a)); if(a == bld->one) return bld->zero; if(a == bld->zero) return bld->one; if(type.norm && !type.floating && !type.fixed && !type.sign) { if(LLVMIsConstant(a)) return LLVMConstNot(a); else return LLVMBuildNot(builder, a, ""); } if(LLVMIsConstant(a)) if (type.floating) return LLVMConstFSub(bld->one, a); else return LLVMConstSub(bld->one, a); else if (type.floating) return LLVMBuildFSub(builder, bld->one, a, ""); else return LLVMBuildSub(builder, bld->one, a, ""); } /** * Generate a + b */ LLVMValueRef lp_build_add(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef b) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMValueRef res; assert(lp_check_value(type, a)); assert(lp_check_value(type, b)); if(a == bld->zero) return b; if(b == bld->zero) return a; if(a == bld->undef || b == bld->undef) return bld->undef; if(bld->type.norm) { const char *intrinsic = NULL; if(a == bld->one || b == bld->one) return bld->one; if(util_cpu_caps.has_sse2 && type.width * type.length == 128 && !type.floating && !type.fixed) { if(type.width == 8) intrinsic = type.sign ? "llvm.x86.sse2.padds.b" : "llvm.x86.sse2.paddus.b"; if(type.width == 16) intrinsic = type.sign ? "llvm.x86.sse2.padds.w" : "llvm.x86.sse2.paddus.w"; } if(intrinsic) return lp_build_intrinsic_binary(builder, intrinsic, lp_build_vec_type(bld->gallivm, bld->type), a, b); } if(LLVMIsConstant(a) && LLVMIsConstant(b)) if (type.floating) res = LLVMConstFAdd(a, b); else res = LLVMConstAdd(a, b); else if (type.floating) res = LLVMBuildFAdd(builder, a, b, ""); else res = LLVMBuildAdd(builder, a, b, ""); /* clamp to ceiling of 1.0 */ if(bld->type.norm && (bld->type.floating || bld->type.fixed)) res = lp_build_min_simple(bld, res, bld->one); /* XXX clamp to floor of -1 or 0??? */ return res; } /** Return the scalar sum of the elements of a */ LLVMValueRef lp_build_sum_vector(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMValueRef index, res; unsigned i; assert(lp_check_value(type, a)); if (type.length == 1) { return a; } assert(!bld->type.norm); index = lp_build_const_int32(bld->gallivm, 0); res = LLVMBuildExtractElement(builder, a, index, ""); for (i = 1; i < type.length; i++) { index = lp_build_const_int32(bld->gallivm, i); if (type.floating) res = LLVMBuildFAdd(builder, res, LLVMBuildExtractElement(builder, a, index, ""), ""); else res = LLVMBuildAdd(builder, res, LLVMBuildExtractElement(builder, a, index, ""), ""); } return res; } /** * Generate a - b */ LLVMValueRef lp_build_sub(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef b) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMValueRef res; assert(lp_check_value(type, a)); assert(lp_check_value(type, b)); if(b == bld->zero) return a; if(a == bld->undef || b == bld->undef) return bld->undef; if(a == b) return bld->zero; if(bld->type.norm) { const char *intrinsic = NULL; if(b == bld->one) return bld->zero; if(util_cpu_caps.has_sse2 && type.width * type.length == 128 && !type.floating && !type.fixed) { if(type.width == 8) intrinsic = type.sign ? "llvm.x86.sse2.psubs.b" : "llvm.x86.sse2.psubus.b"; if(type.width == 16) intrinsic = type.sign ? "llvm.x86.sse2.psubs.w" : "llvm.x86.sse2.psubus.w"; } if(intrinsic) return lp_build_intrinsic_binary(builder, intrinsic, lp_build_vec_type(bld->gallivm, bld->type), a, b); } if(LLVMIsConstant(a) && LLVMIsConstant(b)) if (type.floating) res = LLVMConstFSub(a, b); else res = LLVMConstSub(a, b); else if (type.floating) res = LLVMBuildFSub(builder, a, b, ""); else res = LLVMBuildSub(builder, a, b, ""); if(bld->type.norm && (bld->type.floating || bld->type.fixed)) res = lp_build_max_simple(bld, res, bld->zero); return res; } /** * Normalized 8bit multiplication. * * - alpha plus one * * makes the following approximation to the division (Sree) * * a*b/255 ~= (a*(b + 1)) >> 256 * * which is the fastest method that satisfies the following OpenGL criteria * * 0*0 = 0 and 255*255 = 255 * * - geometric series * * takes the geometric series approximation to the division * * t/255 = (t >> 8) + (t >> 16) + (t >> 24) .. * * in this case just the first two terms to fit in 16bit arithmetic * * t/255 ~= (t + (t >> 8)) >> 8 * * note that just by itself it doesn't satisfies the OpenGL criteria, as * 255*255 = 254, so the special case b = 255 must be accounted or roundoff * must be used * * - geometric series plus rounding * * when using a geometric series division instead of truncating the result * use roundoff in the approximation (Jim Blinn) * * t/255 ~= (t + (t >> 8) + 0x80) >> 8 * * achieving the exact results * * @sa Alvy Ray Smith, Image Compositing Fundamentals, Tech Memo 4, Aug 15, 1995, * ftp://ftp.alvyray.com/Acrobat/4_Comp.pdf * @sa Michael Herf, The "double blend trick", May 2000, * http://www.stereopsis.com/doubleblend.html */ static LLVMValueRef lp_build_mul_u8n(struct gallivm_state *gallivm, struct lp_type i16_type, LLVMValueRef a, LLVMValueRef b) { LLVMBuilderRef builder = gallivm->builder; LLVMValueRef c8; LLVMValueRef ab; assert(!i16_type.floating); assert(lp_check_value(i16_type, a)); assert(lp_check_value(i16_type, b)); c8 = lp_build_const_int_vec(gallivm, i16_type, 8); #if 0 /* a*b/255 ~= (a*(b + 1)) >> 256 */ b = LLVMBuildAdd(builder, b, lp_build_const_int_vec(gallium, i16_type, 1), ""); ab = LLVMBuildMul(builder, a, b, ""); #else /* ab/255 ~= (ab + (ab >> 8) + 0x80) >> 8 */ ab = LLVMBuildMul(builder, a, b, ""); ab = LLVMBuildAdd(builder, ab, LLVMBuildLShr(builder, ab, c8, ""), ""); ab = LLVMBuildAdd(builder, ab, lp_build_const_int_vec(gallivm, i16_type, 0x80), ""); #endif ab = LLVMBuildLShr(builder, ab, c8, ""); return ab; } /** * Generate a * b */ LLVMValueRef lp_build_mul(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef b) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMValueRef shift; LLVMValueRef res; assert(lp_check_value(type, a)); assert(lp_check_value(type, b)); if(a == bld->zero) return bld->zero; if(a == bld->one) return b; if(b == bld->zero) return bld->zero; if(b == bld->one) return a; if(a == bld->undef || b == bld->undef) return bld->undef; if(!type.floating && !type.fixed && type.norm) { if(type.width == 8) { struct lp_type i16_type = lp_wider_type(type); LLVMValueRef al, ah, bl, bh, abl, abh, ab; lp_build_unpack2(bld->gallivm, type, i16_type, a, &al, &ah); lp_build_unpack2(bld->gallivm, type, i16_type, b, &bl, &bh); /* PMULLW, PSRLW, PADDW */ abl = lp_build_mul_u8n(bld->gallivm, i16_type, al, bl); abh = lp_build_mul_u8n(bld->gallivm, i16_type, ah, bh); ab = lp_build_pack2(bld->gallivm, i16_type, type, abl, abh); return ab; } /* FIXME */ assert(0); } if(type.fixed) shift = lp_build_const_int_vec(bld->gallivm, type, type.width/2); else shift = NULL; if(LLVMIsConstant(a) && LLVMIsConstant(b)) { if (type.floating) res = LLVMConstFMul(a, b); else res = LLVMConstMul(a, b); if(shift) { if(type.sign) res = LLVMConstAShr(res, shift); else res = LLVMConstLShr(res, shift); } } else { if (type.floating) res = LLVMBuildFMul(builder, a, b, ""); else res = LLVMBuildMul(builder, a, b, ""); if(shift) { if(type.sign) res = LLVMBuildAShr(builder, res, shift, ""); else res = LLVMBuildLShr(builder, res, shift, ""); } } return res; } /** * Small vector x scale multiplication optimization. */ LLVMValueRef lp_build_mul_imm(struct lp_build_context *bld, LLVMValueRef a, int b) { LLVMBuilderRef builder = bld->gallivm->builder; LLVMValueRef factor; assert(lp_check_value(bld->type, a)); if(b == 0) return bld->zero; if(b == 1) return a; if(b == -1) return lp_build_negate(bld, a); if(b == 2 && bld->type.floating) return lp_build_add(bld, a, a); if(util_is_power_of_two(b)) { unsigned shift = ffs(b) - 1; if(bld->type.floating) { #if 0 /* * Power of two multiplication by directly manipulating the mantissa. * * XXX: This might not be always faster, it will introduce a small error * for multiplication by zero, and it will produce wrong results * for Inf and NaN. */ unsigned mantissa = lp_mantissa(bld->type); factor = lp_build_const_int_vec(bld->gallivm, bld->type, (unsigned long long)shift << mantissa); a = LLVMBuildBitCast(builder, a, lp_build_int_vec_type(bld->type), ""); a = LLVMBuildAdd(builder, a, factor, ""); a = LLVMBuildBitCast(builder, a, lp_build_vec_type(bld->gallivm, bld->type), ""); return a; #endif } else { factor = lp_build_const_vec(bld->gallivm, bld->type, shift); return LLVMBuildShl(builder, a, factor, ""); } } factor = lp_build_const_vec(bld->gallivm, bld->type, (double)b); return lp_build_mul(bld, a, factor); } /** * Generate a / b */ LLVMValueRef lp_build_div(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef b) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; assert(lp_check_value(type, a)); assert(lp_check_value(type, b)); if(a == bld->zero) return bld->zero; if(a == bld->one) return lp_build_rcp(bld, b); if(b == bld->zero) return bld->undef; if(b == bld->one) return a; if(a == bld->undef || b == bld->undef) return bld->undef; if(LLVMIsConstant(a) && LLVMIsConstant(b)) { if (type.floating) return LLVMConstFDiv(a, b); else if (type.sign) return LLVMConstSDiv(a, b); else return LLVMConstUDiv(a, b); } if(util_cpu_caps.has_sse && type.width == 32 && type.length == 4) return lp_build_mul(bld, a, lp_build_rcp(bld, b)); if (type.floating) return LLVMBuildFDiv(builder, a, b, ""); else if (type.sign) return LLVMBuildSDiv(builder, a, b, ""); else return LLVMBuildUDiv(builder, a, b, ""); } /** * Linear interpolation -- without any checks. * * @sa http://www.stereopsis.com/doubleblend.html */ static INLINE LLVMValueRef lp_build_lerp_simple(struct lp_build_context *bld, LLVMValueRef x, LLVMValueRef v0, LLVMValueRef v1) { LLVMBuilderRef builder = bld->gallivm->builder; LLVMValueRef delta; LLVMValueRef res; assert(lp_check_value(bld->type, x)); assert(lp_check_value(bld->type, v0)); assert(lp_check_value(bld->type, v1)); delta = lp_build_sub(bld, v1, v0); res = lp_build_mul(bld, x, delta); res = lp_build_add(bld, v0, res); if (bld->type.fixed) { /* XXX: This step is necessary for lerping 8bit colors stored on 16bits, * but it will be wrong for other uses. Basically we need a more * powerful lp_type, capable of further distinguishing the values * interpretation from the value storage. */ res = LLVMBuildAnd(builder, res, lp_build_const_int_vec(bld->gallivm, bld->type, (1 << bld->type.width/2) - 1), ""); } return res; } /** * Linear interpolation. */ LLVMValueRef lp_build_lerp(struct lp_build_context *bld, LLVMValueRef x, LLVMValueRef v0, LLVMValueRef v1) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMValueRef res; assert(lp_check_value(type, x)); assert(lp_check_value(type, v0)); assert(lp_check_value(type, v1)); if (type.norm) { struct lp_type wide_type; struct lp_build_context wide_bld; LLVMValueRef xl, xh, v0l, v0h, v1l, v1h, resl, resh; LLVMValueRef shift; assert(type.length >= 2); assert(!type.sign); /* * Create a wider type, enough to hold the intermediate result of the * multiplication. */ memset(&wide_type, 0, sizeof wide_type); wide_type.fixed = TRUE; wide_type.width = type.width*2; wide_type.length = type.length/2; lp_build_context_init(&wide_bld, bld->gallivm, wide_type); lp_build_unpack2(bld->gallivm, type, wide_type, x, &xl, &xh); lp_build_unpack2(bld->gallivm, type, wide_type, v0, &v0l, &v0h); lp_build_unpack2(bld->gallivm, type, wide_type, v1, &v1l, &v1h); /* * Scale x from [0, 255] to [0, 256] */ shift = lp_build_const_int_vec(bld->gallivm, wide_type, type.width - 1); xl = lp_build_add(&wide_bld, xl, LLVMBuildAShr(builder, xl, shift, "")); xh = lp_build_add(&wide_bld, xh, LLVMBuildAShr(builder, xh, shift, "")); /* * Lerp both halves. */ resl = lp_build_lerp_simple(&wide_bld, xl, v0l, v1l); resh = lp_build_lerp_simple(&wide_bld, xh, v0h, v1h); res = lp_build_pack2(bld->gallivm, wide_type, type, resl, resh); } else { res = lp_build_lerp_simple(bld, x, v0, v1); } return res; } LLVMValueRef lp_build_lerp_2d(struct lp_build_context *bld, LLVMValueRef x, LLVMValueRef y, LLVMValueRef v00, LLVMValueRef v01, LLVMValueRef v10, LLVMValueRef v11) { LLVMValueRef v0 = lp_build_lerp(bld, x, v00, v01); LLVMValueRef v1 = lp_build_lerp(bld, x, v10, v11); return lp_build_lerp(bld, y, v0, v1); } /** * Generate min(a, b) * Do checks for special cases. */ LLVMValueRef lp_build_min(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef b) { assert(lp_check_value(bld->type, a)); assert(lp_check_value(bld->type, b)); if(a == bld->undef || b == bld->undef) return bld->undef; if(a == b) return a; if(bld->type.norm) { if(a == bld->zero || b == bld->zero) return bld->zero; if(a == bld->one) return b; if(b == bld->one) return a; } return lp_build_min_simple(bld, a, b); } /** * Generate max(a, b) * Do checks for special cases. */ LLVMValueRef lp_build_max(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef b) { assert(lp_check_value(bld->type, a)); assert(lp_check_value(bld->type, b)); if(a == bld->undef || b == bld->undef) return bld->undef; if(a == b) return a; if(bld->type.norm) { if(a == bld->one || b == bld->one) return bld->one; if(a == bld->zero) return b; if(b == bld->zero) return a; } return lp_build_max_simple(bld, a, b); } /** * Generate clamp(a, min, max) * Do checks for special cases. */ LLVMValueRef lp_build_clamp(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef min, LLVMValueRef max) { assert(lp_check_value(bld->type, a)); assert(lp_check_value(bld->type, min)); assert(lp_check_value(bld->type, max)); a = lp_build_min(bld, a, max); a = lp_build_max(bld, a, min); return a; } /** * Generate abs(a) */ LLVMValueRef lp_build_abs(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef vec_type = lp_build_vec_type(bld->gallivm, type); assert(lp_check_value(type, a)); if(!type.sign) return a; if(type.floating) { /* Mask out the sign bit */ LLVMTypeRef int_vec_type = lp_build_int_vec_type(bld->gallivm, type); unsigned long long absMask = ~(1ULL << (type.width - 1)); LLVMValueRef mask = lp_build_const_int_vec(bld->gallivm, type, ((unsigned long long) absMask)); a = LLVMBuildBitCast(builder, a, int_vec_type, ""); a = LLVMBuildAnd(builder, a, mask, ""); a = LLVMBuildBitCast(builder, a, vec_type, ""); return a; } if(type.width*type.length == 128 && util_cpu_caps.has_ssse3) { switch(type.width) { case 8: return lp_build_intrinsic_unary(builder, "llvm.x86.ssse3.pabs.b.128", vec_type, a); case 16: return lp_build_intrinsic_unary(builder, "llvm.x86.ssse3.pabs.w.128", vec_type, a); case 32: return lp_build_intrinsic_unary(builder, "llvm.x86.ssse3.pabs.d.128", vec_type, a); } } return lp_build_max(bld, a, LLVMBuildNeg(builder, a, "")); } LLVMValueRef lp_build_negate(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; assert(lp_check_value(bld->type, a)); #if HAVE_LLVM >= 0x0207 if (bld->type.floating) a = LLVMBuildFNeg(builder, a, ""); else #endif a = LLVMBuildNeg(builder, a, ""); return a; } /** Return -1, 0 or +1 depending on the sign of a */ LLVMValueRef lp_build_sgn(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMValueRef cond; LLVMValueRef res; assert(lp_check_value(type, a)); /* Handle non-zero case */ if(!type.sign) { /* if not zero then sign must be positive */ res = bld->one; } else if(type.floating) { LLVMTypeRef vec_type; LLVMTypeRef int_type; LLVMValueRef mask; LLVMValueRef sign; LLVMValueRef one; unsigned long long maskBit = (unsigned long long)1 << (type.width - 1); int_type = lp_build_int_vec_type(bld->gallivm, type); vec_type = lp_build_vec_type(bld->gallivm, type); mask = lp_build_const_int_vec(bld->gallivm, type, maskBit); /* Take the sign bit and add it to 1 constant */ sign = LLVMBuildBitCast(builder, a, int_type, ""); sign = LLVMBuildAnd(builder, sign, mask, ""); one = LLVMConstBitCast(bld->one, int_type); res = LLVMBuildOr(builder, sign, one, ""); res = LLVMBuildBitCast(builder, res, vec_type, ""); } else { LLVMValueRef minus_one = lp_build_const_vec(bld->gallivm, type, -1.0); cond = lp_build_cmp(bld, PIPE_FUNC_GREATER, a, bld->zero); res = lp_build_select(bld, cond, bld->one, minus_one); } /* Handle zero */ cond = lp_build_cmp(bld, PIPE_FUNC_EQUAL, a, bld->zero); res = lp_build_select(bld, cond, bld->zero, res); return res; } /** * Set the sign of float vector 'a' according to 'sign'. * If sign==0, return abs(a). * If sign==1, return -abs(a); * Other values for sign produce undefined results. */ LLVMValueRef lp_build_set_sign(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef sign) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef int_vec_type = lp_build_int_vec_type(bld->gallivm, type); LLVMTypeRef vec_type = lp_build_vec_type(bld->gallivm, type); LLVMValueRef shift = lp_build_const_int_vec(bld->gallivm, type, type.width - 1); LLVMValueRef mask = lp_build_const_int_vec(bld->gallivm, type, ~((unsigned long long) 1 << (type.width - 1))); LLVMValueRef val, res; assert(type.floating); assert(lp_check_value(type, a)); /* val = reinterpret_cast(a) */ val = LLVMBuildBitCast(builder, a, int_vec_type, ""); /* val = val & mask */ val = LLVMBuildAnd(builder, val, mask, ""); /* sign = sign << shift */ sign = LLVMBuildShl(builder, sign, shift, ""); /* res = val | sign */ res = LLVMBuildOr(builder, val, sign, ""); /* res = reinterpret_cast(res) */ res = LLVMBuildBitCast(builder, res, vec_type, ""); return res; } /** * Convert vector of (or scalar) int to vector of (or scalar) float. */ LLVMValueRef lp_build_int_to_float(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef vec_type = lp_build_vec_type(bld->gallivm, type); assert(type.floating); return LLVMBuildSIToFP(builder, a, vec_type, ""); } enum lp_build_round_sse41_mode { LP_BUILD_ROUND_SSE41_NEAREST = 0, LP_BUILD_ROUND_SSE41_FLOOR = 1, LP_BUILD_ROUND_SSE41_CEIL = 2, LP_BUILD_ROUND_SSE41_TRUNCATE = 3 }; /** * Helper for SSE4.1's ROUNDxx instructions. * * NOTE: In the SSE4.1's nearest mode, if two values are equally close, the * result is the even value. That is, rounding 2.5 will be 2.0, and not 3.0. */ static INLINE LLVMValueRef lp_build_round_sse41(struct lp_build_context *bld, LLVMValueRef a, enum lp_build_round_sse41_mode mode) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef i32t = LLVMInt32TypeInContext(bld->gallivm->context); const char *intrinsic; LLVMValueRef res; assert(type.floating); assert(lp_check_value(type, a)); assert(util_cpu_caps.has_sse4_1); if (type.length == 1) { LLVMTypeRef vec_type; LLVMValueRef undef; LLVMValueRef args[3]; LLVMValueRef index0 = LLVMConstInt(i32t, 0, 0); switch(type.width) { case 32: intrinsic = "llvm.x86.sse41.round.ss"; break; case 64: intrinsic = "llvm.x86.sse41.round.sd"; break; default: assert(0); return bld->undef; } vec_type = LLVMVectorType(bld->elem_type, 4); undef = LLVMGetUndef(vec_type); args[0] = undef; args[1] = LLVMBuildInsertElement(builder, undef, a, index0, ""); args[2] = LLVMConstInt(i32t, mode, 0); res = lp_build_intrinsic(builder, intrinsic, vec_type, args, Elements(args)); res = LLVMBuildExtractElement(builder, res, index0, ""); } else { assert(type.width*type.length == 128); switch(type.width) { case 32: intrinsic = "llvm.x86.sse41.round.ps"; break; case 64: intrinsic = "llvm.x86.sse41.round.pd"; break; default: assert(0); return bld->undef; } res = lp_build_intrinsic_binary(builder, intrinsic, bld->vec_type, a, LLVMConstInt(i32t, mode, 0)); } return res; } static INLINE LLVMValueRef lp_build_iround_nearest_sse2(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef i32t = LLVMInt32TypeInContext(bld->gallivm->context); LLVMTypeRef ret_type = lp_build_int_vec_type(bld->gallivm, type); const char *intrinsic; LLVMValueRef res; assert(type.floating); /* using the double precision conversions is a bit more complicated */ assert(type.width == 32); assert(lp_check_value(type, a)); assert(util_cpu_caps.has_sse2); /* This is relying on MXCSR rounding mode, which should always be nearest. */ if (type.length == 1) { LLVMTypeRef vec_type; LLVMValueRef undef; LLVMValueRef arg; LLVMValueRef index0 = LLVMConstInt(i32t, 0, 0); vec_type = LLVMVectorType(bld->elem_type, 4); intrinsic = "llvm.x86.sse.cvtss2si"; undef = LLVMGetUndef(vec_type); arg = LLVMBuildInsertElement(builder, undef, a, index0, ""); res = lp_build_intrinsic_unary(builder, intrinsic, ret_type, arg); } else { assert(type.width*type.length == 128); intrinsic = "llvm.x86.sse2.cvtps2dq"; res = lp_build_intrinsic_unary(builder, intrinsic, ret_type, a); } return res; } /** * Return the integer part of a float (vector) value (== round toward zero). * The returned value is a float (vector). * Ex: trunc(-1.5) = -1.0 */ LLVMValueRef lp_build_trunc(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; assert(type.floating); assert(lp_check_value(type, a)); if (util_cpu_caps.has_sse4_1 && (type.length == 1 || type.width*type.length == 128)) { return lp_build_round_sse41(bld, a, LP_BUILD_ROUND_SSE41_TRUNCATE); } else { LLVMTypeRef vec_type = lp_build_vec_type(bld->gallivm, type); LLVMTypeRef int_vec_type = lp_build_int_vec_type(bld->gallivm, type); LLVMValueRef res; res = LLVMBuildFPToSI(builder, a, int_vec_type, ""); res = LLVMBuildSIToFP(builder, res, vec_type, ""); return res; } } /** * Return float (vector) rounded to nearest integer (vector). The returned * value is a float (vector). * Ex: round(0.9) = 1.0 * Ex: round(-1.5) = -2.0 */ LLVMValueRef lp_build_round(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; assert(type.floating); assert(lp_check_value(type, a)); if (util_cpu_caps.has_sse4_1 && (type.length == 1 || type.width*type.length == 128)) { return lp_build_round_sse41(bld, a, LP_BUILD_ROUND_SSE41_NEAREST); } else { LLVMTypeRef vec_type = lp_build_vec_type(bld->gallivm, type); LLVMValueRef res; res = lp_build_iround(bld, a); res = LLVMBuildSIToFP(builder, res, vec_type, ""); return res; } } /** * Return floor of float (vector), result is a float (vector) * Ex: floor(1.1) = 1.0 * Ex: floor(-1.1) = -2.0 */ LLVMValueRef lp_build_floor(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; assert(type.floating); assert(lp_check_value(type, a)); if (util_cpu_caps.has_sse4_1 && (type.length == 1 || type.width*type.length == 128)) { return lp_build_round_sse41(bld, a, LP_BUILD_ROUND_SSE41_FLOOR); } else { LLVMTypeRef vec_type = lp_build_vec_type(bld->gallivm, type); LLVMValueRef res; res = lp_build_ifloor(bld, a); res = LLVMBuildSIToFP(builder, res, vec_type, ""); return res; } } /** * Return ceiling of float (vector), returning float (vector). * Ex: ceil( 1.1) = 2.0 * Ex: ceil(-1.1) = -1.0 */ LLVMValueRef lp_build_ceil(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; assert(type.floating); assert(lp_check_value(type, a)); if (util_cpu_caps.has_sse4_1 && (type.length == 1 || type.width*type.length == 128)) { return lp_build_round_sse41(bld, a, LP_BUILD_ROUND_SSE41_CEIL); } else { LLVMTypeRef vec_type = lp_build_vec_type(bld->gallivm, type); LLVMValueRef res; res = lp_build_iceil(bld, a); res = LLVMBuildSIToFP(builder, res, vec_type, ""); return res; } } /** * Return fractional part of 'a' computed as a - floor(a) * Typically used in texture coord arithmetic. */ LLVMValueRef lp_build_fract(struct lp_build_context *bld, LLVMValueRef a) { assert(bld->type.floating); return lp_build_sub(bld, a, lp_build_floor(bld, a)); } /** * Return the integer part of a float (vector) value (== round toward zero). * The returned value is an integer (vector). * Ex: itrunc(-1.5) = -1 */ LLVMValueRef lp_build_itrunc(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef int_vec_type = lp_build_int_vec_type(bld->gallivm, type); assert(type.floating); assert(lp_check_value(type, a)); return LLVMBuildFPToSI(builder, a, int_vec_type, ""); } /** * Return float (vector) rounded to nearest integer (vector). The returned * value is an integer (vector). * Ex: iround(0.9) = 1 * Ex: iround(-1.5) = -2 */ LLVMValueRef lp_build_iround(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef int_vec_type = bld->int_vec_type; LLVMValueRef res; assert(type.floating); assert(lp_check_value(type, a)); if (util_cpu_caps.has_sse2 && ((type.width == 32) && (type.length == 1 || type.length == 4))) { return lp_build_iround_nearest_sse2(bld, a); } else if (util_cpu_caps.has_sse4_1 && (type.length == 1 || type.width*type.length == 128)) { res = lp_build_round_sse41(bld, a, LP_BUILD_ROUND_SSE41_NEAREST); } else { LLVMValueRef half; half = lp_build_const_vec(bld->gallivm, type, 0.5); if (type.sign) { LLVMTypeRef vec_type = bld->vec_type; LLVMValueRef mask = lp_build_const_int_vec(bld->gallivm, type, (unsigned long long)1 << (type.width - 1)); LLVMValueRef sign; /* get sign bit */ sign = LLVMBuildBitCast(builder, a, int_vec_type, ""); sign = LLVMBuildAnd(builder, sign, mask, ""); /* sign * 0.5 */ half = LLVMBuildBitCast(builder, half, int_vec_type, ""); half = LLVMBuildOr(builder, sign, half, ""); half = LLVMBuildBitCast(builder, half, vec_type, ""); } res = LLVMBuildFAdd(builder, a, half, ""); } res = LLVMBuildFPToSI(builder, res, int_vec_type, ""); return res; } /** * Return floor of float (vector), result is an int (vector) * Ex: ifloor(1.1) = 1.0 * Ex: ifloor(-1.1) = -2.0 */ LLVMValueRef lp_build_ifloor(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef int_vec_type = bld->int_vec_type; LLVMValueRef res; assert(type.floating); assert(lp_check_value(type, a)); if (util_cpu_caps.has_sse4_1 && (type.length == 1 || type.width*type.length == 128)) { res = lp_build_round_sse41(bld, a, LP_BUILD_ROUND_SSE41_FLOOR); } else { res = a; if (type.sign) { /* Take the sign bit and add it to 1 constant */ LLVMTypeRef vec_type = bld->vec_type; unsigned mantissa = lp_mantissa(type); LLVMValueRef mask = lp_build_const_int_vec(bld->gallivm, type, (unsigned long long)1 << (type.width - 1)); LLVMValueRef sign; LLVMValueRef offset; /* sign = a < 0 ? ~0 : 0 */ sign = LLVMBuildBitCast(builder, a, int_vec_type, ""); sign = LLVMBuildAnd(builder, sign, mask, ""); sign = LLVMBuildAShr(builder, sign, lp_build_const_int_vec(bld->gallivm, type, type.width - 1), "ifloor.sign"); /* offset = -0.99999(9)f */ offset = lp_build_const_vec(bld->gallivm, type, -(double)(((unsigned long long)1 << mantissa) - 10)/((unsigned long long)1 << mantissa)); offset = LLVMConstBitCast(offset, int_vec_type); /* offset = a < 0 ? offset : 0.0f */ offset = LLVMBuildAnd(builder, offset, sign, ""); offset = LLVMBuildBitCast(builder, offset, vec_type, "ifloor.offset"); res = LLVMBuildFAdd(builder, res, offset, "ifloor.res"); } } /* round to nearest (toward zero) */ res = LLVMBuildFPToSI(builder, res, int_vec_type, "ifloor.res"); return res; } /** * Return ceiling of float (vector), returning int (vector). * Ex: iceil( 1.1) = 2 * Ex: iceil(-1.1) = -1 */ LLVMValueRef lp_build_iceil(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef int_vec_type = bld->int_vec_type; LLVMValueRef res; assert(type.floating); assert(lp_check_value(type, a)); if (util_cpu_caps.has_sse4_1 && (type.length == 1 || type.width*type.length == 128)) { res = lp_build_round_sse41(bld, a, LP_BUILD_ROUND_SSE41_CEIL); } else { LLVMTypeRef vec_type = bld->vec_type; unsigned mantissa = lp_mantissa(type); LLVMValueRef offset; /* offset = 0.99999(9)f */ offset = lp_build_const_vec(bld->gallivm, type, (double)(((unsigned long long)1 << mantissa) - 10)/((unsigned long long)1 << mantissa)); if (type.sign) { LLVMValueRef mask = lp_build_const_int_vec(bld->gallivm, type, (unsigned long long)1 << (type.width - 1)); LLVMValueRef sign; /* sign = a < 0 ? 0 : ~0 */ sign = LLVMBuildBitCast(builder, a, int_vec_type, ""); sign = LLVMBuildAnd(builder, sign, mask, ""); sign = LLVMBuildAShr(builder, sign, lp_build_const_int_vec(bld->gallivm, type, type.width - 1), "iceil.sign"); sign = LLVMBuildNot(builder, sign, "iceil.not"); /* offset = a < 0 ? 0.0 : offset */ offset = LLVMConstBitCast(offset, int_vec_type); offset = LLVMBuildAnd(builder, offset, sign, ""); offset = LLVMBuildBitCast(builder, offset, vec_type, "iceil.offset"); } res = LLVMBuildFAdd(builder, a, offset, "iceil.res"); } /* round to nearest (toward zero) */ res = LLVMBuildFPToSI(builder, res, int_vec_type, "iceil.res"); return res; } /** * Combined ifloor() & fract(). * * Preferred to calling the functions separately, as it will ensure that the * stratergy (floor() vs ifloor()) that results in less redundant work is used. */ void lp_build_ifloor_fract(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef *out_ipart, LLVMValueRef *out_fpart) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMValueRef ipart; assert(type.floating); assert(lp_check_value(type, a)); if (util_cpu_caps.has_sse4_1 && (type.length == 1 || type.width*type.length == 128)) { /* * floor() is easier. */ ipart = lp_build_floor(bld, a); *out_fpart = LLVMBuildFSub(builder, a, ipart, "fpart"); *out_ipart = LLVMBuildFPToSI(builder, ipart, bld->int_vec_type, "ipart"); } else { /* * ifloor() is easier. */ *out_ipart = lp_build_ifloor(bld, a); ipart = LLVMBuildSIToFP(builder, *out_ipart, bld->vec_type, "ipart"); *out_fpart = LLVMBuildFSub(builder, a, ipart, "fpart"); } } LLVMValueRef lp_build_sqrt(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef vec_type = lp_build_vec_type(bld->gallivm, type); char intrinsic[32]; assert(lp_check_value(type, a)); /* TODO: optimize the constant case */ /* TODO: optimize the constant case */ assert(type.floating); util_snprintf(intrinsic, sizeof intrinsic, "llvm.sqrt.v%uf%u", type.length, type.width); return lp_build_intrinsic_unary(builder, intrinsic, vec_type, a); } /** * Do one Newton-Raphson step to improve reciprocate precision: * * x_{i+1} = x_i * (2 - a * x_i) * * XXX: Unfortunately this won't give IEEE-754 conformant results for 0 or * +/-Inf, giving NaN instead. Certain applications rely on this behavior, * such as Google Earth, which does RCP(RSQRT(0.0) when drawing the Earth's * halo. It would be necessary to clamp the argument to prevent this. * * See also: * - http://en.wikipedia.org/wiki/Division_(digital)#Newton.E2.80.93Raphson_division * - http://softwarecommunity.intel.com/articles/eng/1818.htm */ static INLINE LLVMValueRef lp_build_rcp_refine(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef rcp_a) { LLVMBuilderRef builder = bld->gallivm->builder; LLVMValueRef two = lp_build_const_vec(bld->gallivm, bld->type, 2.0); LLVMValueRef res; res = LLVMBuildFMul(builder, a, rcp_a, ""); res = LLVMBuildFSub(builder, two, res, ""); res = LLVMBuildFMul(builder, rcp_a, res, ""); return res; } LLVMValueRef lp_build_rcp(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; assert(lp_check_value(type, a)); if(a == bld->zero) return bld->undef; if(a == bld->one) return bld->one; if(a == bld->undef) return bld->undef; assert(type.floating); if(LLVMIsConstant(a)) return LLVMConstFDiv(bld->one, a); /* * We don't use RCPPS because: * - it only has 10bits of precision * - it doesn't even get the reciprocate of 1.0 exactly * - doing Newton-Rapshon steps yields wrong (NaN) values for 0.0 or Inf * - for recent processors the benefit over DIVPS is marginal, a case * depedent * * We could still use it on certain processors if benchmarks show that the * RCPPS plus necessary workarounds are still preferrable to DIVPS; or for * particular uses that require less workarounds. */ if (FALSE && util_cpu_caps.has_sse && type.width == 32 && type.length == 4) { const unsigned num_iterations = 0; LLVMValueRef res; unsigned i; res = lp_build_intrinsic_unary(builder, "llvm.x86.sse.rcp.ps", bld->vec_type, a); for (i = 0; i < num_iterations; ++i) { res = lp_build_rcp_refine(bld, a, res); } return res; } return LLVMBuildFDiv(builder, bld->one, a, ""); } /** * Do one Newton-Raphson step to improve rsqrt precision: * * x_{i+1} = 0.5 * x_i * (3.0 - a * x_i * x_i) * * See also: * - http://softwarecommunity.intel.com/articles/eng/1818.htm */ static INLINE LLVMValueRef lp_build_rsqrt_refine(struct lp_build_context *bld, LLVMValueRef a, LLVMValueRef rsqrt_a) { LLVMBuilderRef builder = bld->gallivm->builder; LLVMValueRef half = lp_build_const_vec(bld->gallivm, bld->type, 0.5); LLVMValueRef three = lp_build_const_vec(bld->gallivm, bld->type, 3.0); LLVMValueRef res; res = LLVMBuildFMul(builder, rsqrt_a, rsqrt_a, ""); res = LLVMBuildFMul(builder, a, res, ""); res = LLVMBuildFSub(builder, three, res, ""); res = LLVMBuildFMul(builder, rsqrt_a, res, ""); res = LLVMBuildFMul(builder, half, res, ""); return res; } /** * Generate 1/sqrt(a) */ LLVMValueRef lp_build_rsqrt(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; assert(lp_check_value(type, a)); assert(type.floating); if (util_cpu_caps.has_sse && type.width == 32 && type.length == 4) { const unsigned num_iterations = 1; LLVMValueRef res; unsigned i; res = lp_build_intrinsic_unary(builder, "llvm.x86.sse.rsqrt.ps", bld->vec_type, a); for (i = 0; i < num_iterations; ++i) { res = lp_build_rsqrt_refine(bld, a, res); } return res; } return lp_build_rcp(bld, lp_build_sqrt(bld, a)); } static inline LLVMValueRef lp_build_const_v4si(struct gallivm_state *gallivm, unsigned long value) { LLVMValueRef element = lp_build_const_int32(gallivm, value); LLVMValueRef elements[4] = { element, element, element, element }; return LLVMConstVector(elements, 4); } static inline LLVMValueRef lp_build_const_v4sf(struct gallivm_state *gallivm, float value) { LLVMValueRef element = lp_build_const_float(gallivm, value); LLVMValueRef elements[4] = { element, element, element, element }; return LLVMConstVector(elements, 4); } /** * Generate sin(a) using SSE2 */ LLVMValueRef lp_build_sin(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; struct gallivm_state *gallivm = bld->gallivm; struct lp_type int_type = lp_int_type(bld->type); LLVMBuilderRef b = builder; LLVMTypeRef v4sf = LLVMVectorType(LLVMFloatTypeInContext(bld->gallivm->context), 4); LLVMTypeRef v4si = LLVMVectorType(LLVMInt32TypeInContext(bld->gallivm->context), 4); /* * take the absolute value, * x = _mm_and_ps(x, *(v4sf*)_ps_inv_sign_mask); */ LLVMValueRef inv_sig_mask = lp_build_const_v4si(bld->gallivm, ~0x80000000); LLVMValueRef a_v4si = LLVMBuildBitCast(b, a, v4si, "a_v4si"); LLVMValueRef absi = LLVMBuildAnd(b, a_v4si, inv_sig_mask, "absi"); LLVMValueRef x_abs = LLVMBuildBitCast(b, absi, v4sf, "x_abs"); /* * extract the sign bit (upper one) * sign_bit = _mm_and_ps(sign_bit, *(v4sf*)_ps_sign_mask); */ LLVMValueRef sig_mask = lp_build_const_v4si(bld->gallivm, 0x80000000); LLVMValueRef sign_bit_i = LLVMBuildAnd(b, a_v4si, sig_mask, "sign_bit_i"); /* * scale by 4/Pi * y = _mm_mul_ps(x, *(v4sf*)_ps_cephes_FOPI); */ LLVMValueRef FOPi = lp_build_const_v4sf(gallivm, 1.27323954473516); LLVMValueRef scale_y = LLVMBuildFMul(b, x_abs, FOPi, "scale_y"); /* * store the integer part of y in mm0 * emm2 = _mm_cvttps_epi32(y); */ LLVMValueRef emm2_i = LLVMBuildFPToSI(b, scale_y, v4si, "emm2_i"); /* * j=(j+1) & (~1) (see the cephes sources) * emm2 = _mm_add_epi32(emm2, *(v4si*)_pi32_1); */ LLVMValueRef all_one = lp_build_const_v4si(bld->gallivm, 1); LLVMValueRef emm2_add = LLVMBuildAdd(b, emm2_i, all_one, "emm2_add"); /* * emm2 = _mm_and_si128(emm2, *(v4si*)_pi32_inv1); */ LLVMValueRef inv_one = lp_build_const_v4si(bld->gallivm, ~1); LLVMValueRef emm2_and = LLVMBuildAnd(b, emm2_add, inv_one, "emm2_and"); /* * y = _mm_cvtepi32_ps(emm2); */ LLVMValueRef y_2 = LLVMBuildSIToFP(b, emm2_and, v4sf, "y_2"); /* get the swap sign flag * emm0 = _mm_and_si128(emm2, *(v4si*)_pi32_4); */ LLVMValueRef pi32_4 = lp_build_const_v4si(bld->gallivm, 4); LLVMValueRef emm0_and = LLVMBuildAnd(b, emm2_add, pi32_4, "emm0_and"); /* * emm2 = _mm_slli_epi32(emm0, 29); */ LLVMValueRef const_29 = lp_build_const_v4si(bld->gallivm, 29); LLVMValueRef swap_sign_bit = LLVMBuildShl(b, emm0_and, const_29, "swap_sign_bit"); /* * get the polynom selection mask * there is one polynom for 0 <= x <= Pi/4 * and another one for Pi/4gallivm, 2); LLVMValueRef emm2_3 = LLVMBuildAnd(b, emm2_and, pi32_2, "emm2_3"); LLVMValueRef poly_mask = lp_build_compare(bld->gallivm, int_type, PIPE_FUNC_EQUAL, emm2_3, lp_build_const_v4si(bld->gallivm, 0)); /* * sign_bit = _mm_xor_ps(sign_bit, swap_sign_bit); */ LLVMValueRef sign_bit_1 = LLVMBuildXor(b, sign_bit_i, swap_sign_bit, "sign_bit"); /* * _PS_CONST(minus_cephes_DP1, -0.78515625); * _PS_CONST(minus_cephes_DP2, -2.4187564849853515625e-4); * _PS_CONST(minus_cephes_DP3, -3.77489497744594108e-8); */ LLVMValueRef DP1 = lp_build_const_v4sf(gallivm, -0.78515625); LLVMValueRef DP2 = lp_build_const_v4sf(gallivm, -2.4187564849853515625e-4); LLVMValueRef DP3 = lp_build_const_v4sf(gallivm, -3.77489497744594108e-8); /* * The magic pass: "Extended precision modular arithmetic" * x = ((x - y * DP1) - y * DP2) - y * DP3; * xmm1 = _mm_mul_ps(y, xmm1); * xmm2 = _mm_mul_ps(y, xmm2); * xmm3 = _mm_mul_ps(y, xmm3); */ LLVMValueRef xmm1 = LLVMBuildFMul(b, y_2, DP1, "xmm1"); LLVMValueRef xmm2 = LLVMBuildFMul(b, y_2, DP2, "xmm2"); LLVMValueRef xmm3 = LLVMBuildFMul(b, y_2, DP3, "xmm3"); /* * x = _mm_add_ps(x, xmm1); * x = _mm_add_ps(x, xmm2); * x = _mm_add_ps(x, xmm3); */ LLVMValueRef x_1 = LLVMBuildFAdd(b, x_abs, xmm1, "x_1"); LLVMValueRef x_2 = LLVMBuildFAdd(b, x_1, xmm2, "x_2"); LLVMValueRef x_3 = LLVMBuildFAdd(b, x_2, xmm3, "x_3"); /* * Evaluate the first polynom (0 <= x <= Pi/4) * * z = _mm_mul_ps(x,x); */ LLVMValueRef z = LLVMBuildFMul(b, x_3, x_3, "z"); /* * _PS_CONST(coscof_p0, 2.443315711809948E-005); * _PS_CONST(coscof_p1, -1.388731625493765E-003); * _PS_CONST(coscof_p2, 4.166664568298827E-002); */ LLVMValueRef coscof_p0 = lp_build_const_v4sf(gallivm, 2.443315711809948E-005); LLVMValueRef coscof_p1 = lp_build_const_v4sf(gallivm, -1.388731625493765E-003); LLVMValueRef coscof_p2 = lp_build_const_v4sf(gallivm, 4.166664568298827E-002); /* * y = *(v4sf*)_ps_coscof_p0; * y = _mm_mul_ps(y, z); */ LLVMValueRef y_3 = LLVMBuildFMul(b, z, coscof_p0, "y_3"); LLVMValueRef y_4 = LLVMBuildFAdd(b, y_3, coscof_p1, "y_4"); LLVMValueRef y_5 = LLVMBuildFMul(b, y_4, z, "y_5"); LLVMValueRef y_6 = LLVMBuildFAdd(b, y_5, coscof_p2, "y_6"); LLVMValueRef y_7 = LLVMBuildFMul(b, y_6, z, "y_7"); LLVMValueRef y_8 = LLVMBuildFMul(b, y_7, z, "y_8"); /* * tmp = _mm_mul_ps(z, *(v4sf*)_ps_0p5); * y = _mm_sub_ps(y, tmp); * y = _mm_add_ps(y, *(v4sf*)_ps_1); */ LLVMValueRef half = lp_build_const_v4sf(gallivm, 0.5); LLVMValueRef tmp = LLVMBuildFMul(b, z, half, "tmp"); LLVMValueRef y_9 = LLVMBuildFSub(b, y_8, tmp, "y_8"); LLVMValueRef one = lp_build_const_v4sf(gallivm, 1.0); LLVMValueRef y_10 = LLVMBuildFAdd(b, y_9, one, "y_9"); /* * _PS_CONST(sincof_p0, -1.9515295891E-4); * _PS_CONST(sincof_p1, 8.3321608736E-3); * _PS_CONST(sincof_p2, -1.6666654611E-1); */ LLVMValueRef sincof_p0 = lp_build_const_v4sf(gallivm, -1.9515295891E-4); LLVMValueRef sincof_p1 = lp_build_const_v4sf(gallivm, 8.3321608736E-3); LLVMValueRef sincof_p2 = lp_build_const_v4sf(gallivm, -1.6666654611E-1); /* * Evaluate the second polynom (Pi/4 <= x <= 0) * * y2 = *(v4sf*)_ps_sincof_p0; * y2 = _mm_mul_ps(y2, z); * y2 = _mm_add_ps(y2, *(v4sf*)_ps_sincof_p1); * y2 = _mm_mul_ps(y2, z); * y2 = _mm_add_ps(y2, *(v4sf*)_ps_sincof_p2); * y2 = _mm_mul_ps(y2, z); * y2 = _mm_mul_ps(y2, x); * y2 = _mm_add_ps(y2, x); */ LLVMValueRef y2_3 = LLVMBuildFMul(b, z, sincof_p0, "y2_3"); LLVMValueRef y2_4 = LLVMBuildFAdd(b, y2_3, sincof_p1, "y2_4"); LLVMValueRef y2_5 = LLVMBuildFMul(b, y2_4, z, "y2_5"); LLVMValueRef y2_6 = LLVMBuildFAdd(b, y2_5, sincof_p2, "y2_6"); LLVMValueRef y2_7 = LLVMBuildFMul(b, y2_6, z, "y2_7"); LLVMValueRef y2_8 = LLVMBuildFMul(b, y2_7, x_3, "y2_8"); LLVMValueRef y2_9 = LLVMBuildFAdd(b, y2_8, x_3, "y2_9"); /* * select the correct result from the two polynoms * xmm3 = poly_mask; * y2 = _mm_and_ps(xmm3, y2); //, xmm3); * y = _mm_andnot_ps(xmm3, y); * y = _mm_add_ps(y,y2); */ LLVMValueRef y2_i = LLVMBuildBitCast(b, y2_9, v4si, "y2_i"); LLVMValueRef y_i = LLVMBuildBitCast(b, y_10, v4si, "y_i"); LLVMValueRef y2_and = LLVMBuildAnd(b, y2_i, poly_mask, "y2_and"); LLVMValueRef inv = lp_build_const_v4si(bld->gallivm, ~0); LLVMValueRef poly_mask_inv = LLVMBuildXor(b, poly_mask, inv, "poly_mask_inv"); LLVMValueRef y_and = LLVMBuildAnd(b, y_i, poly_mask_inv, "y_and"); LLVMValueRef y_combine = LLVMBuildAdd(b, y_and, y2_and, "y_combine"); /* * update the sign * y = _mm_xor_ps(y, sign_bit); */ LLVMValueRef y_sign = LLVMBuildXor(b, y_combine, sign_bit_1, "y_sin"); LLVMValueRef y_result = LLVMBuildBitCast(b, y_sign, v4sf, "y_result"); return y_result; } /** * Generate cos(a) using SSE2 */ LLVMValueRef lp_build_cos(struct lp_build_context *bld, LLVMValueRef a) { LLVMBuilderRef builder = bld->gallivm->builder; struct gallivm_state *gallivm = bld->gallivm; struct lp_type int_type = lp_int_type(bld->type); LLVMBuilderRef b = builder; LLVMTypeRef v4sf = LLVMVectorType(LLVMFloatTypeInContext(bld->gallivm->context), 4); LLVMTypeRef v4si = LLVMVectorType(LLVMInt32TypeInContext(bld->gallivm->context), 4); /* * take the absolute value, * x = _mm_and_ps(x, *(v4sf*)_ps_inv_sign_mask); */ LLVMValueRef inv_sig_mask = lp_build_const_v4si(bld->gallivm, ~0x80000000); LLVMValueRef a_v4si = LLVMBuildBitCast(b, a, v4si, "a_v4si"); LLVMValueRef absi = LLVMBuildAnd(b, a_v4si, inv_sig_mask, "absi"); LLVMValueRef x_abs = LLVMBuildBitCast(b, absi, v4sf, "x_abs"); /* * scale by 4/Pi * y = _mm_mul_ps(x, *(v4sf*)_ps_cephes_FOPI); */ LLVMValueRef FOPi = lp_build_const_v4sf(gallivm, 1.27323954473516); LLVMValueRef scale_y = LLVMBuildFMul(b, x_abs, FOPi, "scale_y"); /* * store the integer part of y in mm0 * emm2 = _mm_cvttps_epi32(y); */ LLVMValueRef emm2_i = LLVMBuildFPToSI(b, scale_y, v4si, "emm2_i"); /* * j=(j+1) & (~1) (see the cephes sources) * emm2 = _mm_add_epi32(emm2, *(v4si*)_pi32_1); */ LLVMValueRef all_one = lp_build_const_v4si(bld->gallivm, 1); LLVMValueRef emm2_add = LLVMBuildAdd(b, emm2_i, all_one, "emm2_add"); /* * emm2 = _mm_and_si128(emm2, *(v4si*)_pi32_inv1); */ LLVMValueRef inv_one = lp_build_const_v4si(bld->gallivm, ~1); LLVMValueRef emm2_and = LLVMBuildAnd(b, emm2_add, inv_one, "emm2_and"); /* * y = _mm_cvtepi32_ps(emm2); */ LLVMValueRef y_2 = LLVMBuildSIToFP(b, emm2_and, v4sf, "y_2"); /* * emm2 = _mm_sub_epi32(emm2, *(v4si*)_pi32_2); */ LLVMValueRef const_2 = lp_build_const_v4si(bld->gallivm, 2); LLVMValueRef emm2_2 = LLVMBuildSub(b, emm2_and, const_2, "emm2_2"); /* get the swap sign flag * emm0 = _mm_andnot_si128(emm2, *(v4si*)_pi32_4); */ LLVMValueRef inv = lp_build_const_v4si(bld->gallivm, ~0); LLVMValueRef emm0_not = LLVMBuildXor(b, emm2_2, inv, "emm0_not"); LLVMValueRef pi32_4 = lp_build_const_v4si(bld->gallivm, 4); LLVMValueRef emm0_and = LLVMBuildAnd(b, emm0_not, pi32_4, "emm0_and"); /* * emm2 = _mm_slli_epi32(emm0, 29); */ LLVMValueRef const_29 = lp_build_const_v4si(bld->gallivm, 29); LLVMValueRef sign_bit = LLVMBuildShl(b, emm0_and, const_29, "sign_bit"); /* * get the polynom selection mask * there is one polynom for 0 <= x <= Pi/4 * and another one for Pi/4gallivm, 2); LLVMValueRef emm2_3 = LLVMBuildAnd(b, emm2_2, pi32_2, "emm2_3"); LLVMValueRef poly_mask = lp_build_compare(bld->gallivm, int_type, PIPE_FUNC_EQUAL, emm2_3, lp_build_const_v4si(bld->gallivm, 0)); /* * _PS_CONST(minus_cephes_DP1, -0.78515625); * _PS_CONST(minus_cephes_DP2, -2.4187564849853515625e-4); * _PS_CONST(minus_cephes_DP3, -3.77489497744594108e-8); */ LLVMValueRef DP1 = lp_build_const_v4sf(gallivm, -0.78515625); LLVMValueRef DP2 = lp_build_const_v4sf(gallivm, -2.4187564849853515625e-4); LLVMValueRef DP3 = lp_build_const_v4sf(gallivm, -3.77489497744594108e-8); /* * The magic pass: "Extended precision modular arithmetic" * x = ((x - y * DP1) - y * DP2) - y * DP3; * xmm1 = _mm_mul_ps(y, xmm1); * xmm2 = _mm_mul_ps(y, xmm2); * xmm3 = _mm_mul_ps(y, xmm3); */ LLVMValueRef xmm1 = LLVMBuildFMul(b, y_2, DP1, "xmm1"); LLVMValueRef xmm2 = LLVMBuildFMul(b, y_2, DP2, "xmm2"); LLVMValueRef xmm3 = LLVMBuildFMul(b, y_2, DP3, "xmm3"); /* * x = _mm_add_ps(x, xmm1); * x = _mm_add_ps(x, xmm2); * x = _mm_add_ps(x, xmm3); */ LLVMValueRef x_1 = LLVMBuildFAdd(b, x_abs, xmm1, "x_1"); LLVMValueRef x_2 = LLVMBuildFAdd(b, x_1, xmm2, "x_2"); LLVMValueRef x_3 = LLVMBuildFAdd(b, x_2, xmm3, "x_3"); /* * Evaluate the first polynom (0 <= x <= Pi/4) * * z = _mm_mul_ps(x,x); */ LLVMValueRef z = LLVMBuildFMul(b, x_3, x_3, "z"); /* * _PS_CONST(coscof_p0, 2.443315711809948E-005); * _PS_CONST(coscof_p1, -1.388731625493765E-003); * _PS_CONST(coscof_p2, 4.166664568298827E-002); */ LLVMValueRef coscof_p0 = lp_build_const_v4sf(gallivm, 2.443315711809948E-005); LLVMValueRef coscof_p1 = lp_build_const_v4sf(gallivm, -1.388731625493765E-003); LLVMValueRef coscof_p2 = lp_build_const_v4sf(gallivm, 4.166664568298827E-002); /* * y = *(v4sf*)_ps_coscof_p0; * y = _mm_mul_ps(y, z); */ LLVMValueRef y_3 = LLVMBuildFMul(b, z, coscof_p0, "y_3"); LLVMValueRef y_4 = LLVMBuildFAdd(b, y_3, coscof_p1, "y_4"); LLVMValueRef y_5 = LLVMBuildFMul(b, y_4, z, "y_5"); LLVMValueRef y_6 = LLVMBuildFAdd(b, y_5, coscof_p2, "y_6"); LLVMValueRef y_7 = LLVMBuildFMul(b, y_6, z, "y_7"); LLVMValueRef y_8 = LLVMBuildFMul(b, y_7, z, "y_8"); /* * tmp = _mm_mul_ps(z, *(v4sf*)_ps_0p5); * y = _mm_sub_ps(y, tmp); * y = _mm_add_ps(y, *(v4sf*)_ps_1); */ LLVMValueRef half = lp_build_const_v4sf(gallivm, 0.5); LLVMValueRef tmp = LLVMBuildFMul(b, z, half, "tmp"); LLVMValueRef y_9 = LLVMBuildFSub(b, y_8, tmp, "y_8"); LLVMValueRef one = lp_build_const_v4sf(gallivm, 1.0); LLVMValueRef y_10 = LLVMBuildFAdd(b, y_9, one, "y_9"); /* * _PS_CONST(sincof_p0, -1.9515295891E-4); * _PS_CONST(sincof_p1, 8.3321608736E-3); * _PS_CONST(sincof_p2, -1.6666654611E-1); */ LLVMValueRef sincof_p0 = lp_build_const_v4sf(gallivm, -1.9515295891E-4); LLVMValueRef sincof_p1 = lp_build_const_v4sf(gallivm, 8.3321608736E-3); LLVMValueRef sincof_p2 = lp_build_const_v4sf(gallivm, -1.6666654611E-1); /* * Evaluate the second polynom (Pi/4 <= x <= 0) * * y2 = *(v4sf*)_ps_sincof_p0; * y2 = _mm_mul_ps(y2, z); * y2 = _mm_add_ps(y2, *(v4sf*)_ps_sincof_p1); * y2 = _mm_mul_ps(y2, z); * y2 = _mm_add_ps(y2, *(v4sf*)_ps_sincof_p2); * y2 = _mm_mul_ps(y2, z); * y2 = _mm_mul_ps(y2, x); * y2 = _mm_add_ps(y2, x); */ LLVMValueRef y2_3 = LLVMBuildFMul(b, z, sincof_p0, "y2_3"); LLVMValueRef y2_4 = LLVMBuildFAdd(b, y2_3, sincof_p1, "y2_4"); LLVMValueRef y2_5 = LLVMBuildFMul(b, y2_4, z, "y2_5"); LLVMValueRef y2_6 = LLVMBuildFAdd(b, y2_5, sincof_p2, "y2_6"); LLVMValueRef y2_7 = LLVMBuildFMul(b, y2_6, z, "y2_7"); LLVMValueRef y2_8 = LLVMBuildFMul(b, y2_7, x_3, "y2_8"); LLVMValueRef y2_9 = LLVMBuildFAdd(b, y2_8, x_3, "y2_9"); /* * select the correct result from the two polynoms * xmm3 = poly_mask; * y2 = _mm_and_ps(xmm3, y2); //, xmm3); * y = _mm_andnot_ps(xmm3, y); * y = _mm_add_ps(y,y2); */ LLVMValueRef y2_i = LLVMBuildBitCast(b, y2_9, v4si, "y2_i"); LLVMValueRef y_i = LLVMBuildBitCast(b, y_10, v4si, "y_i"); LLVMValueRef y2_and = LLVMBuildAnd(b, y2_i, poly_mask, "y2_and"); LLVMValueRef poly_mask_inv = LLVMBuildXor(b, poly_mask, inv, "poly_mask_inv"); LLVMValueRef y_and = LLVMBuildAnd(b, y_i, poly_mask_inv, "y_and"); LLVMValueRef y_combine = LLVMBuildAdd(b, y_and, y2_and, "y_combine"); /* * update the sign * y = _mm_xor_ps(y, sign_bit); */ LLVMValueRef y_sign = LLVMBuildXor(b, y_combine, sign_bit, "y_sin"); LLVMValueRef y_result = LLVMBuildBitCast(b, y_sign, v4sf, "y_result"); return y_result; } /** * Generate pow(x, y) */ LLVMValueRef lp_build_pow(struct lp_build_context *bld, LLVMValueRef x, LLVMValueRef y) { /* TODO: optimize the constant case */ if (gallivm_debug & GALLIVM_DEBUG_PERF && LLVMIsConstant(x) && LLVMIsConstant(y)) { debug_printf("%s: inefficient/imprecise constant arithmetic\n", __FUNCTION__); } return lp_build_exp2(bld, lp_build_mul(bld, lp_build_log2(bld, x), y)); } /** * Generate exp(x) */ LLVMValueRef lp_build_exp(struct lp_build_context *bld, LLVMValueRef x) { /* log2(e) = 1/log(2) */ LLVMValueRef log2e = lp_build_const_vec(bld->gallivm, bld->type, 1.4426950408889634); assert(lp_check_value(bld->type, x)); return lp_build_exp2(bld, lp_build_mul(bld, log2e, x)); } /** * Generate log(x) */ LLVMValueRef lp_build_log(struct lp_build_context *bld, LLVMValueRef x) { /* log(2) */ LLVMValueRef log2 = lp_build_const_vec(bld->gallivm, bld->type, 0.69314718055994529); assert(lp_check_value(bld->type, x)); return lp_build_mul(bld, log2, lp_build_log2(bld, x)); } /** * Generate polynomial. * Ex: coeffs[0] + x * coeffs[1] + x^2 * coeffs[2]. */ static LLVMValueRef lp_build_polynomial(struct lp_build_context *bld, LLVMValueRef x, const double *coeffs, unsigned num_coeffs) { const struct lp_type type = bld->type; LLVMValueRef res = NULL; unsigned i; assert(lp_check_value(bld->type, x)); /* TODO: optimize the constant case */ if (gallivm_debug & GALLIVM_DEBUG_PERF && LLVMIsConstant(x)) { debug_printf("%s: inefficient/imprecise constant arithmetic\n", __FUNCTION__); } for (i = num_coeffs; i--; ) { LLVMValueRef coeff; coeff = lp_build_const_vec(bld->gallivm, type, coeffs[i]); if(res) res = lp_build_add(bld, coeff, lp_build_mul(bld, x, res)); else res = coeff; } if(res) return res; else return bld->undef; } /** * Minimax polynomial fit of 2**x, in range [0, 1[ */ const double lp_build_exp2_polynomial[] = { #if EXP_POLY_DEGREE == 5 0.999999925063526176901, 0.693153073200168932794, 0.240153617044375388211, 0.0558263180532956664775, 0.00898934009049466391101, 0.00187757667519147912699 #elif EXP_POLY_DEGREE == 4 1.00000259337069434683, 0.693003834469974940458, 0.24144275689150793076, 0.0520114606103070150235, 0.0135341679161270268764 #elif EXP_POLY_DEGREE == 3 0.999925218562710312959, 0.695833540494823811697, 0.226067155427249155588, 0.0780245226406372992967 #elif EXP_POLY_DEGREE == 2 1.00172476321474503578, 0.657636275736077639316, 0.33718943461968720704 #else #error #endif }; void lp_build_exp2_approx(struct lp_build_context *bld, LLVMValueRef x, LLVMValueRef *p_exp2_int_part, LLVMValueRef *p_frac_part, LLVMValueRef *p_exp2) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef vec_type = lp_build_vec_type(bld->gallivm, type); LLVMValueRef ipart = NULL; LLVMValueRef fpart = NULL; LLVMValueRef expipart = NULL; LLVMValueRef expfpart = NULL; LLVMValueRef res = NULL; assert(lp_check_value(bld->type, x)); if(p_exp2_int_part || p_frac_part || p_exp2) { /* TODO: optimize the constant case */ if (gallivm_debug & GALLIVM_DEBUG_PERF && LLVMIsConstant(x)) { debug_printf("%s: inefficient/imprecise constant arithmetic\n", __FUNCTION__); } assert(type.floating && type.width == 32); x = lp_build_min(bld, x, lp_build_const_vec(bld->gallivm, type, 129.0)); x = lp_build_max(bld, x, lp_build_const_vec(bld->gallivm, type, -126.99999)); /* ipart = floor(x) */ /* fpart = x - ipart */ lp_build_ifloor_fract(bld, x, &ipart, &fpart); } if(p_exp2_int_part || p_exp2) { /* expipart = (float) (1 << ipart) */ expipart = LLVMBuildAdd(builder, ipart, lp_build_const_int_vec(bld->gallivm, type, 127), ""); expipart = LLVMBuildShl(builder, expipart, lp_build_const_int_vec(bld->gallivm, type, 23), ""); expipart = LLVMBuildBitCast(builder, expipart, vec_type, ""); } if(p_exp2) { expfpart = lp_build_polynomial(bld, fpart, lp_build_exp2_polynomial, Elements(lp_build_exp2_polynomial)); res = LLVMBuildFMul(builder, expipart, expfpart, ""); } if(p_exp2_int_part) *p_exp2_int_part = expipart; if(p_frac_part) *p_frac_part = fpart; if(p_exp2) *p_exp2 = res; } LLVMValueRef lp_build_exp2(struct lp_build_context *bld, LLVMValueRef x) { LLVMValueRef res; lp_build_exp2_approx(bld, x, NULL, NULL, &res); return res; } /** * Extract the exponent of a IEEE-754 floating point value. * * Optionally apply an integer bias. * * Result is an integer value with * * ifloor(log2(x)) + bias */ LLVMValueRef lp_build_extract_exponent(struct lp_build_context *bld, LLVMValueRef x, int bias) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; unsigned mantissa = lp_mantissa(type); LLVMValueRef res; assert(type.floating); assert(lp_check_value(bld->type, x)); x = LLVMBuildBitCast(builder, x, bld->int_vec_type, ""); res = LLVMBuildLShr(builder, x, lp_build_const_int_vec(bld->gallivm, type, mantissa), ""); res = LLVMBuildAnd(builder, res, lp_build_const_int_vec(bld->gallivm, type, 255), ""); res = LLVMBuildSub(builder, res, lp_build_const_int_vec(bld->gallivm, type, 127 - bias), ""); return res; } /** * Extract the mantissa of the a floating. * * Result is a floating point value with * * x / floor(log2(x)) */ LLVMValueRef lp_build_extract_mantissa(struct lp_build_context *bld, LLVMValueRef x) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; unsigned mantissa = lp_mantissa(type); LLVMValueRef mantmask = lp_build_const_int_vec(bld->gallivm, type, (1ULL << mantissa) - 1); LLVMValueRef one = LLVMConstBitCast(bld->one, bld->int_vec_type); LLVMValueRef res; assert(lp_check_value(bld->type, x)); assert(type.floating); x = LLVMBuildBitCast(builder, x, bld->int_vec_type, ""); /* res = x / 2**ipart */ res = LLVMBuildAnd(builder, x, mantmask, ""); res = LLVMBuildOr(builder, res, one, ""); res = LLVMBuildBitCast(builder, res, bld->vec_type, ""); return res; } /** * Minimax polynomial fit of log2(x)/(x - 1), for x in range [1, 2[ * These coefficients can be generate with * http://www.boost.org/doc/libs/1_36_0/libs/math/doc/sf_and_dist/html/math_toolkit/toolkit/internals2/minimax.html */ const double lp_build_log2_polynomial[] = { #if LOG_POLY_DEGREE == 6 3.11578814719469302614, -3.32419399085241980044, 2.59883907202499966007, -1.23152682416275988241, 0.318212422185251071475, -0.0344359067839062357313 #elif LOG_POLY_DEGREE == 5 2.8882704548164776201, -2.52074962577807006663, 1.48116647521213171641, -0.465725644288844778798, 0.0596515482674574969533 #elif LOG_POLY_DEGREE == 4 2.61761038894603480148, -1.75647175389045657003, 0.688243882994381274313, -0.107254423828329604454 #elif LOG_POLY_DEGREE == 3 2.28330284476918490682, -1.04913055217340124191, 0.204446009836232697516 #else #error #endif }; /** * See http://www.devmaster.net/forums/showthread.php?p=43580 */ void lp_build_log2_approx(struct lp_build_context *bld, LLVMValueRef x, LLVMValueRef *p_exp, LLVMValueRef *p_floor_log2, LLVMValueRef *p_log2) { LLVMBuilderRef builder = bld->gallivm->builder; const struct lp_type type = bld->type; LLVMTypeRef vec_type = lp_build_vec_type(bld->gallivm, type); LLVMTypeRef int_vec_type = lp_build_int_vec_type(bld->gallivm, type); LLVMValueRef expmask = lp_build_const_int_vec(bld->gallivm, type, 0x7f800000); LLVMValueRef mantmask = lp_build_const_int_vec(bld->gallivm, type, 0x007fffff); LLVMValueRef one = LLVMConstBitCast(bld->one, int_vec_type); LLVMValueRef i = NULL; LLVMValueRef exp = NULL; LLVMValueRef mant = NULL; LLVMValueRef logexp = NULL; LLVMValueRef logmant = NULL; LLVMValueRef res = NULL; assert(lp_check_value(bld->type, x)); if(p_exp || p_floor_log2 || p_log2) { /* TODO: optimize the constant case */ if (gallivm_debug & GALLIVM_DEBUG_PERF && LLVMIsConstant(x)) { debug_printf("%s: inefficient/imprecise constant arithmetic\n", __FUNCTION__); } assert(type.floating && type.width == 32); /* * We don't explicitly handle denormalized numbers. They will yield a * result in the neighbourhood of -127, which appears to be adequate * enough. */ i = LLVMBuildBitCast(builder, x, int_vec_type, ""); /* exp = (float) exponent(x) */ exp = LLVMBuildAnd(builder, i, expmask, ""); } if(p_floor_log2 || p_log2) { logexp = LLVMBuildLShr(builder, exp, lp_build_const_int_vec(bld->gallivm, type, 23), ""); logexp = LLVMBuildSub(builder, logexp, lp_build_const_int_vec(bld->gallivm, type, 127), ""); logexp = LLVMBuildSIToFP(builder, logexp, vec_type, ""); } if(p_log2) { /* mant = (float) mantissa(x) */ mant = LLVMBuildAnd(builder, i, mantmask, ""); mant = LLVMBuildOr(builder, mant, one, ""); mant = LLVMBuildBitCast(builder, mant, vec_type, ""); logmant = lp_build_polynomial(bld, mant, lp_build_log2_polynomial, Elements(lp_build_log2_polynomial)); /* This effectively increases the polynomial degree by one, but ensures that log2(1) == 0*/ logmant = LLVMBuildFMul(builder, logmant, LLVMBuildFSub(builder, mant, bld->one, ""), ""); res = LLVMBuildFAdd(builder, logmant, logexp, ""); } if(p_exp) { exp = LLVMBuildBitCast(builder, exp, vec_type, ""); *p_exp = exp; } if(p_floor_log2) *p_floor_log2 = logexp; if(p_log2) *p_log2 = res; } LLVMValueRef lp_build_log2(struct lp_build_context *bld, LLVMValueRef x) { LLVMValueRef res; lp_build_log2_approx(bld, x, NULL, NULL, &res); return res; } /** * Faster (and less accurate) log2. * * log2(x) = floor(log2(x)) - 1 + x / 2**floor(log2(x)) * * Piece-wise linear approximation, with exact results when x is a * power of two. * * See http://www.flipcode.com/archives/Fast_log_Function.shtml */ LLVMValueRef lp_build_fast_log2(struct lp_build_context *bld, LLVMValueRef x) { LLVMBuilderRef builder = bld->gallivm->builder; LLVMValueRef ipart; LLVMValueRef fpart; assert(lp_check_value(bld->type, x)); assert(bld->type.floating); /* ipart = floor(log2(x)) - 1 */ ipart = lp_build_extract_exponent(bld, x, -1); ipart = LLVMBuildSIToFP(builder, ipart, bld->vec_type, ""); /* fpart = x / 2**ipart */ fpart = lp_build_extract_mantissa(bld, x); /* ipart + fpart */ return LLVMBuildFAdd(builder, ipart, fpart, ""); } /** * Fast implementation of iround(log2(x)). * * Not an approximation -- it should give accurate results all the time. */ LLVMValueRef lp_build_ilog2(struct lp_build_context *bld, LLVMValueRef x) { LLVMBuilderRef builder = bld->gallivm->builder; LLVMValueRef sqrt2 = lp_build_const_vec(bld->gallivm, bld->type, M_SQRT2); LLVMValueRef ipart; assert(bld->type.floating); assert(lp_check_value(bld->type, x)); /* x * 2^(0.5) i.e., add 0.5 to the log2(x) */ x = LLVMBuildFMul(builder, x, sqrt2, ""); /* ipart = floor(log2(x) + 0.5) */ ipart = lp_build_extract_exponent(bld, x, 0); return ipart; }