nir: add int_to_float lowering pass

This new pass lowers ints and bools to floats. It allows hardware
that doesn't have native integers (e.g. Mali4x0) use the same
code paths as modern hardware.

It uses newly introduced pass to gather SSA types and should be
used as late as possible.

Reviewed-by: Jason Ekstrand <[email protected]>
Reviewed-by: Christian Gmeiner <[email protected]>
Signed-off-by: Vasily Khoruzhick <[email protected]>

4 files changed, 215 insertions, 0 deletions

diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
index 005256725ff..7a2f790fcfa 100644
--- a/src/compiler/Makefile.sources
+++ b/src/compiler/Makefile.sources
@@ -254,6 +254,7 @@ NIR_FILES = \
 	nir/nir_lower_idiv.c \
 	nir/nir_lower_indirect_derefs.c \
 	nir/nir_lower_int64.c \
+	nir/nir_lower_int_to_float.c \
 	nir/nir_lower_io.c \
 	nir/nir_lower_io_arrays_to_elements.c \
 	nir/nir_lower_io_to_temporaries.c \
diff --git a/src/compiler/nir/meson.build b/src/compiler/nir/meson.build
index a8faeb9c018..6ea2776d5f3 100644
--- a/src/compiler/nir/meson.build
+++ b/src/compiler/nir/meson.build
@@ -134,6 +134,7 @@ files_libnir = files(
   'nir_lower_idiv.c',
   'nir_lower_indirect_derefs.c',
   'nir_lower_int64.c',
+  'nir_lower_int_to_float.c',
   'nir_lower_io.c',
   'nir_lower_io_arrays_to_elements.c',
   'nir_lower_io_to_temporaries.c',
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 37161e83e4d..450f10a70b9 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -3183,6 +3183,7 @@ bool nir_lower_alu(nir_shader *shader);
 bool nir_lower_alu_to_scalar(nir_shader *shader);
 bool nir_lower_bool_to_float(nir_shader *shader);
 bool nir_lower_bool_to_int32(nir_shader *shader);
+bool nir_lower_int_to_float(nir_shader *shader);
 bool nir_lower_load_const_to_scalar(nir_shader *shader);
 bool nir_lower_read_invocation_to_scalar(nir_shader *shader);
 bool nir_lower_phis_to_scalar(nir_shader *shader);
diff --git a/src/compiler/nir/nir_lower_int_to_float.c b/src/compiler/nir/nir_lower_int_to_float.c
new file mode 100644
index 00000000000..439afa0cdbd
--- /dev/null
+++ b/src/compiler/nir/nir_lower_int_to_float.c
@@ -0,0 +1,212 @@
+/*
+ * Copyright © 2018 Intel Corporation
+ * Copyright © 2019 Vasily Khoruzhick <[email protected]>
+ *
+ * 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, sublicense,
+ * 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 NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS 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.
+ */
+
+#include "nir.h"
+#include "nir_builder.h"
+
+static bool
+assert_ssa_def_is_not_int(nir_ssa_def *def, void *arg)
+{
+   BITSET_WORD *int_types = arg;
+   assert(!BITSET_TEST(int_types, def->index));
+   return true;
+}
+
+static bool
+rewrite_bool_ssa_def_to_float(nir_ssa_def *def, void *_progress)
+{
+   bool *progress = _progress;
+   if (def->bit_size == 1) {
+      def->bit_size = 32;
+      *progress = true;
+   }
+   return true;
+}
+
+static bool
+lower_alu_instr(nir_builder *b, nir_alu_instr *alu)
+{
+   const nir_op_info *op_info = &nir_op_infos[alu->op];
+
+   b->cursor = nir_before_instr(&alu->instr);
+
+   /* Replacement SSA value */
+   nir_ssa_def *rep = NULL;
+   switch (alu->op) {
+   case nir_op_vec2:
+   case nir_op_vec3:
+   case nir_op_vec4:
+      /* These we expect to have integers or booleans but the opcode doesn't change */
+      break;
+
+   case nir_op_b2f32: alu->op = nir_op_fmov; break;
+   case nir_op_b2i32: alu->op = nir_op_fmov; break;
+   case nir_op_i2f32: alu->op = nir_op_fmov; break;
+   case nir_op_f2i32: alu->op = nir_op_fmov; break;
+   case nir_op_f2i1:
+   case nir_op_f2b1:
+   case nir_op_i2b1:
+      rep = nir_sne(b, nir_ssa_for_alu_src(b, alu, 0),
+                       nir_imm_float(b, 0));
+      break;
+
+   case nir_op_flt: alu->op = nir_op_slt; break;
+   case nir_op_fge: alu->op = nir_op_sge; break;
+   case nir_op_feq: alu->op = nir_op_seq; break;
+   case nir_op_fne: alu->op = nir_op_sne; break;
+   case nir_op_ilt: alu->op = nir_op_slt; break;
+   case nir_op_ige: alu->op = nir_op_sge; break;
+   case nir_op_ieq: alu->op = nir_op_seq; break;
+   case nir_op_ine: alu->op = nir_op_sne; break;
+   case nir_op_ult: alu->op = nir_op_slt; break;
+   case nir_op_uge: alu->op = nir_op_sge; break;
+   case nir_op_ineg: alu->op = nir_op_fneg; break;
+
+   case nir_op_ball_fequal2:  alu->op = nir_op_fall_equal2; break;
+   case nir_op_ball_fequal3:  alu->op = nir_op_fall_equal3; break;
+   case nir_op_ball_fequal4:  alu->op = nir_op_fall_equal4; break;
+   case nir_op_bany_fnequal2: alu->op = nir_op_fany_nequal2; break;
+   case nir_op_bany_fnequal3: alu->op = nir_op_fany_nequal3; break;
+   case nir_op_bany_fnequal4: alu->op = nir_op_fany_nequal4; break;
+   case nir_op_ball_iequal2:  alu->op = nir_op_fall_equal2; break;
+   case nir_op_ball_iequal3:  alu->op = nir_op_fall_equal3; break;
+   case nir_op_ball_iequal4:  alu->op = nir_op_fall_equal4; break;
+   case nir_op_bany_inequal2: alu->op = nir_op_fany_nequal2; break;
+   case nir_op_bany_inequal3: alu->op = nir_op_fany_nequal3; break;
+   case nir_op_bany_inequal4: alu->op = nir_op_fany_nequal4; break;
+
+   case nir_op_bcsel: alu->op = nir_op_fcsel; break;
+
+   case nir_op_iadd: alu->op = nir_op_fadd; break;
+   case nir_op_isub: alu->op = nir_op_fsub; break;
+   case nir_op_imul: alu->op = nir_op_fmul; break;
+   case nir_op_imov: alu->op = nir_op_fmov; break;
+   case nir_op_iand: alu->op = nir_op_fmul; break;
+   case nir_op_ixor: alu->op = nir_op_sne; break;
+   case nir_op_ior: alu->op = nir_op_fmax; break;
+
+   case nir_op_idiv:
+      rep = nir_ftrunc(b, nir_fdiv(b,
+                                   nir_ssa_for_alu_src(b, alu, 0),
+                                   nir_ssa_for_alu_src(b, alu, 1)));
+      break;
+
+   case nir_op_inot:
+      rep = nir_seq(b, nir_ssa_for_alu_src(b, alu, 0),
+                       nir_imm_float(b, 0));
+      break;
+
+   default:
+      assert(alu->dest.dest.ssa.bit_size > 1);
+      for (unsigned i = 0; i < op_info->num_inputs; i++)
+         assert(alu->src[i].src.ssa->bit_size > 1);
+      return false;
+   }
+
+   if (rep) {
+      /* We've emitted a replacement instruction */
+      nir_ssa_def_rewrite_uses(&alu->dest.dest.ssa, nir_src_for_ssa(rep));
+      nir_instr_remove(&alu->instr);
+   } else {
+      if (alu->dest.dest.ssa.bit_size == 1)
+         alu->dest.dest.ssa.bit_size = 32;
+   }
+
+   return true;
+}
+
+static bool
+nir_lower_int_to_float_impl(nir_function_impl *impl)
+{
+   bool progress = false;
+   BITSET_WORD *float_types = NULL, *int_types = NULL;
+
+   nir_builder b;
+   nir_builder_init(&b, impl);
+
+   nir_index_ssa_defs(impl);
+   float_types = calloc(BITSET_WORDS(impl->ssa_alloc),
+                        sizeof(BITSET_WORD));
+   int_types = calloc(BITSET_WORDS(impl->ssa_alloc),
+                      sizeof(BITSET_WORD));
+   nir_gather_ssa_types(impl, float_types, int_types);
+
+   nir_foreach_block(block, impl) {
+      nir_foreach_instr_safe(instr, block) {
+         switch (instr->type) {
+         case nir_instr_type_alu:
+            progress |= lower_alu_instr(&b, nir_instr_as_alu(instr));
+            break;
+
+         case nir_instr_type_load_const: {
+            nir_load_const_instr *load = nir_instr_as_load_const(instr);
+            if (load->def.bit_size == 1) {
+               for (unsigned i = 0; i < load->def.num_components; i++)
+                  load->value[i].f32 = load->value[i].b ? 1.0 : 0.0;
+               load->def.bit_size = 32;
+            } else if (BITSET_TEST(int_types, load->def.index)) {
+               for (unsigned i = 0; i < load->def.num_components; i++)
+                  load->value[i].f32 = load->value[i].i32;
+            }
+            break;
+         }
+
+         case nir_instr_type_intrinsic:
+         case nir_instr_type_ssa_undef:
+         case nir_instr_type_phi:
+         case nir_instr_type_tex:
+            nir_foreach_ssa_def(instr, rewrite_bool_ssa_def_to_float,
+                                &progress);
+            break;
+
+         default:
+            nir_foreach_ssa_def(instr, assert_ssa_def_is_not_int, (void *)int_types);
+            break;
+         }
+      }
+   }
+
+   if (progress) {
+      nir_metadata_preserve(impl, nir_metadata_block_index |
+                                  nir_metadata_dominance);
+   }
+
+   free(float_types);
+   free(int_types);
+
+   return progress;
+}
+
+bool
+nir_lower_int_to_float(nir_shader *shader)
+{
+   bool progress = false;
+
+   nir_foreach_function(function, shader) {
+      if (function->impl && nir_lower_int_to_float_impl(function->impl))
+         progress = true;
+   }
+
+   return progress;
+}