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-rw-r--r--src/gallium/auxiliary/gallivm/lp_bld_conv.c105
1 files changed, 75 insertions, 30 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_conv.c b/src/gallium/auxiliary/gallivm/lp_bld_conv.c
index cd18b0c6520..dc3649db363 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_conv.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_conv.c
@@ -63,15 +63,18 @@
#include "util/u_debug.h"
#include "util/u_math.h"
+#include "util/u_half.h"
#include "util/u_cpu_detect.h"
#include "lp_bld_type.h"
#include "lp_bld_const.h"
#include "lp_bld_arit.h"
+#include "lp_bld_bitarit.h"
#include "lp_bld_pack.h"
#include "lp_bld_conv.h"
#include "lp_bld_logic.h"
#include "lp_bld_intr.h"
+#include "lp_bld_printf.h"
@@ -220,64 +223,106 @@ lp_build_half_to_float(struct gallivm_state *gallivm,
*
* ref http://fgiesen.wordpress.com/2012/03/28/half-to-float-done-quic/
* ref https://gist.github.com/2156668
+ *
+ * XXX: This is an approximation. It is faster but certain NaNs are converted to
+ * infinity, and rounding is not correct.
*/
LLVMValueRef
lp_build_float_to_half(struct gallivm_state *gallivm,
LLVMValueRef src)
{
- struct lp_type i32_type = lp_type_int_vec(32, 32 * LLVMGetVectorSize(LLVMTypeOf(src)));
-
LLVMBuilderRef builder = gallivm->builder;
- LLVMTypeRef int_vec_type = lp_build_vec_type(gallivm, i32_type);
-
- struct lp_build_context bld;
-
+ LLVMTypeRef f32_vec_type = LLVMTypeOf(src);
+ unsigned length = LLVMGetTypeKind(f32_vec_type) == LLVMVectorTypeKind
+ ? LLVMGetVectorSize(f32_vec_type) : 1;
+ struct lp_type f32_type = lp_type_float_vec(32, 32 * length);
+ struct lp_type u32_type = lp_type_uint_vec(32, 32 * length);
+ struct lp_type i16_type = lp_type_int_vec(16, 16 * length);
+ LLVMTypeRef u32_vec_type = lp_build_vec_type(gallivm, u32_type);
+ LLVMTypeRef i16_vec_type = lp_build_vec_type(gallivm, i16_type);
+ struct lp_build_context f32_bld;
+ struct lp_build_context u32_bld;
LLVMValueRef result;
- lp_build_context_init(&bld, gallivm, i32_type);
+ lp_build_context_init(&f32_bld, gallivm, f32_type);
+ lp_build_context_init(&u32_bld, gallivm, u32_type);
- /* Extra scope because lp_build_min needs a build context, le sigh */
{
/* Constants */
- LLVMValueRef i32_13 = lp_build_const_int_vec(gallivm, i32_type, 13);
- LLVMValueRef i32_16 = lp_build_const_int_vec(gallivm, i32_type, 16);
- LLVMValueRef i32_mask_fabs = lp_build_const_int_vec(gallivm, i32_type, 0x7fffffff);
- LLVMValueRef i32_f32infty = lp_build_const_int_vec(gallivm, i32_type, 0xff << 23);
- LLVMValueRef i32_expinf = lp_build_const_int_vec(gallivm, i32_type, 0xe0 << 23);
- LLVMValueRef i32_f16max = lp_build_const_int_vec(gallivm, i32_type, 0x8f << 23);
- LLVMValueRef i32_magic = lp_build_const_int_vec(gallivm, i32_type, 0x0f << 23);
+ LLVMValueRef u32_f32inf = lp_build_const_int_vec(gallivm, u32_type, 0xff << 23);
+ LLVMValueRef u32_expinf = lp_build_const_int_vec(gallivm, u32_type, 0xe0 << 23);
+ LLVMValueRef f32_f16max = lp_build_const_vec(gallivm, f32_type, 65536.0); // 0x8f << 23
+ LLVMValueRef f32_magic = lp_build_const_vec(gallivm, f32_type, 1.92592994e-34); // 0x0f << 23
/* Cast from float32 to int32 */
- LLVMValueRef f = LLVMBuildBitCast(builder, src, int_vec_type, "");
+ LLVMValueRef f = LLVMBuildBitCast(builder, src, u32_vec_type, "");
/* Remove sign */
- LLVMValueRef fabs = LLVMBuildAnd(builder, i32_mask_fabs, f, "");
+ LLVMValueRef srcabs = lp_build_abs(&f32_bld, src);
+ LLVMValueRef fabs = LLVMBuildBitCast(builder, srcabs, u32_vec_type, "");
/* Magic conversion */
- LLVMValueRef clamped = lp_build_min(&bld, i32_f16max, fabs);
- LLVMValueRef scaled = LLVMBuildMul(builder, clamped, i32_magic, "");
-
+ LLVMValueRef clamped = lp_build_min(&f32_bld, f32_f16max, srcabs);
+ LLVMValueRef scaled = LLVMBuildBitCast(builder,
+ LLVMBuildFMul(builder,
+ clamped,
+ f32_magic,
+ ""),
+ u32_vec_type,
+ "");
/* Make sure Inf/NaN and unormalised survive */
- LLVMValueRef infnancase = LLVMBuildXor(builder, i32_expinf, fabs, "");
- LLVMValueRef b_notnormal = lp_build_compare(gallivm, i32_type, PIPE_FUNC_GREATER, fabs, i32_f32infty);
+ LLVMValueRef infnancase = LLVMBuildXor(builder, u32_expinf, fabs, "");
+ LLVMValueRef b_notnormal = lp_build_compare(gallivm, f32_type, PIPE_FUNC_GEQUAL,
+ srcabs,
+ LLVMBuildBitCast(builder, u32_f32inf, f32_vec_type, ""));
/* Merge normal / unnormal case */
- LLVMValueRef merge1 = LLVMBuildAnd(builder, infnancase, b_notnormal, "");
- LLVMValueRef merge2 = LLVMBuildNot(builder, LLVMBuildAnd(builder, b_notnormal, scaled, ""), "");
- LLVMValueRef merged = LLVMBuildOr(builder, merge1, merge2, "");
- LLVMValueRef shifted = LLVMBuildLShr(builder, merged, i32_13, "");
+ LLVMValueRef merged = lp_build_select(&u32_bld, b_notnormal, infnancase, scaled);
+ LLVMValueRef shifted = lp_build_shr_imm(&u32_bld, merged, 13);
/* Sign bit */
LLVMValueRef justsign = LLVMBuildXor(builder, f, fabs, "");
- LLVMValueRef signshifted = LLVMBuildLShr(builder, justsign, i32_16, "");
+ LLVMValueRef signshifted = lp_build_shr_imm(&u32_bld, justsign, 16);
/* Combine result */
result = LLVMBuildOr(builder, shifted, signshifted, "");
}
- /* Truncate from 32 bit to 16 bit */
- i32_type.width = 16;
- return LLVMBuildTrunc(builder, result, lp_build_vec_type(gallivm, i32_type), "");
+ result = LLVMBuildTrunc(builder, result, i16_vec_type, "");
+
+ /*
+ * Debugging code.
+ */
+ if (0) {
+ LLVMTypeRef i32t = LLVMInt32TypeInContext(gallivm->context);
+ LLVMTypeRef i16t = LLVMInt16TypeInContext(gallivm->context);
+ LLVMTypeRef f32t = LLVMFloatTypeInContext(gallivm->context);
+ LLVMValueRef ref_result = LLVMGetUndef(LLVMVectorType(i16t, length));
+ unsigned i;
+
+ LLVMTypeRef func_type = LLVMFunctionType(i16t, &f32t, 1, 0);
+ LLVMValueRef func = lp_build_const_int_pointer(gallivm, func_to_pointer((func_pointer)util_float_to_half));
+ func = LLVMBuildBitCast(builder, func, LLVMPointerType(func_type, 0), "util_float_to_half");
+
+ for (i = 0; i < length; ++i) {
+ LLVMValueRef index = LLVMConstInt(i32t, i, 0);
+ LLVMValueRef f32 = LLVMBuildExtractElement(builder, src, index, "");
+#if 0
+ /* XXX: not really supported by backends */
+ LLVMValueRef f16 = lp_build_intrinsic_unary(builder, "llvm.convert.to.fp16", i16t, f32);
+#else
+ LLVMValueRef f16 = LLVMBuildCall(builder, func, &f32, 1, "");
+#endif
+ ref_result = LLVMBuildInsertElement(builder, ref_result, f16, index, "");
+ }
+
+ lp_build_print_value(gallivm, "src = ", src);
+ lp_build_print_value(gallivm, "llvm = ", result);
+ lp_build_print_value(gallivm, "util = ", ref_result);
+ lp_build_printf(gallivm, "\n");
+ }
+
+ return result;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-29 17:30:41 +0000