From ac64b78f1f38a0dea0e7d21bc58b96a9ab061c4e Mon Sep 17 00:00:00 2001
From: Ian Romanick <ian.d.romanick@intel.com>
Date: Thu, 10 Oct 2024 14:09:04 -0700
Subject: [PATCH] brw/copy: Perform constant folding with constant propagation

No shader-db or fossil-db changes on any Intel platform.

v2: Simlify the logic for when to try constant folding. Do
commute_immediates before constant folding. Both suggested by Ken.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31729>
---
 .../compiler/brw_fs_copy_propagation.cpp      | 27 ++++++++++---------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/src/intel/compiler/brw_fs_copy_propagation.cpp b/src/intel/compiler/brw_fs_copy_propagation.cpp
index 84369d97f2f..92c00760986 100644
--- a/src/intel/compiler/brw_fs_copy_propagation.cpp
+++ b/src/intel/compiler/brw_fs_copy_propagation.cpp
@@ -1318,7 +1318,7 @@ opt_copy_propagation_local(const brw_compiler *compiler, linear_ctx *lin_ctx,
 
    foreach_inst_in_block(fs_inst, inst, block) {
       /* Try propagating into this instruction. */
-      bool instruction_progress = false;
+      bool constant_progress = false;
       for (int i = inst->sources - 1; i >= 0; i--) {
          if (inst->src[i].file != VGRF)
             continue;
@@ -1328,22 +1328,23 @@ opt_copy_propagation_local(const brw_compiler *compiler, linear_ctx *lin_ctx,
               ++iter) {
             if ((*iter)->src.file == IMM) {
                if (try_constant_propagate(inst, *iter, i)) {
-                  instruction_progress = true;
+                  constant_progress = true;
                   break;
                }
             } else {
                if (try_copy_propagate(compiler, inst, *iter, i, alloc,
                                       max_polygons)) {
-                  instruction_progress = true;
+                  progress = true;
                   break;
                }
             }
          }
       }
 
-      if (instruction_progress) {
-         progress = true;
+      if (constant_progress) {
          commute_immediates(inst);
+         brw_constant_fold_instruction(compiler->devinfo, inst);
+         progress = true;
       }
 
       /* kill the destination from the ACP */
@@ -1803,7 +1804,7 @@ brw_fs_opt_copy_propagation_defs(fs_visitor &s)
 
    foreach_block_and_inst_safe(block, fs_inst, inst, s.cfg) {
       /* Try propagating into this instruction. */
-      bool instruction_progress = false;
+      bool constant_progress = false;
 
       for (int i = inst->sources - 1; i >= 0; i--) {
          fs_inst *def = defs.get(inst->src[i]);
@@ -1822,7 +1823,7 @@ brw_fs_opt_copy_propagation_defs(fs_visitor &s)
                                          inst, i, s.max_polygons);
 
                if (source_progress) {
-                  instruction_progress = true;
+                  progress = true;
                   ++uses_deleted[def->dst.nr];
                   if (defs.get_use_count(def->dst) == uses_deleted[def->dst.nr])
                      def->remove(defs.get_block(def->dst), true);
@@ -1836,8 +1837,10 @@ brw_fs_opt_copy_propagation_defs(fs_visitor &s)
             find_value_for_offset(def, inst->src[i], inst->size_read(i));
 
          if (val.file == IMM) {
-            source_progress =
-               try_constant_propagate_def(def, val, inst, i);
+            if (try_constant_propagate_def(def, val, inst, i)) {
+               source_progress = true;
+               constant_progress = true;
+            }
          } else if (val.file == VGRF ||
                     val.file == ATTR || val.file == UNIFORM ||
                     (val.file == FIXED_GRF && val.is_contiguous())) {
@@ -1847,7 +1850,7 @@ brw_fs_opt_copy_propagation_defs(fs_visitor &s)
          }
 
          if (source_progress) {
-            instruction_progress = true;
+            progress = true;
             ++uses_deleted[def->dst.nr];
 
             /* We can copy propagate through an instruction like
@@ -1863,9 +1866,9 @@ brw_fs_opt_copy_propagation_defs(fs_visitor &s)
          }
       }
 
-      if (instruction_progress) {
-         progress = true;
+      if (constant_progress) {
          commute_immediates(inst);
+         brw_constant_fold_instruction(s.compiler->devinfo, inst);
       }
    }