[Mesa-dev] [PATCH] nir/copy_propagate: do not copy-propagate MOV srcs with source modifiers

[Iago Toral Quiroga]

If a source operand in a MOV has source modifiers, then we cannot
copy-propagate it from the parent instruction and remove the MOV.

v2: remove the check for source source modifiers from is_move() (Jason)
---
 src/glsl/nir/nir_opt_copy_propagate.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/glsl/nir/nir_opt_copy_propagate.c b/src/glsl/nir/nir_opt_copy_propagate.c
index 7d8bdd7..2611069 100644
--- a/src/glsl/nir/nir_opt_copy_propagate.c
+++ b/src/glsl/nir/nir_opt_copy_propagate.c
@@ -41,11 +41,6 @@ static bool is_move(nir_alu_instr *instr)
    if (instr->dest.saturate)
       return false;
 
-   /* we handle modifiers in a separate pass */
-
-   if (instr->src[0].abs || instr->src[0].negate)
-      return false;
-
    if (!instr->src[0].src.is_ssa)
       return false;
 
@@ -65,9 +60,13 @@ static bool is_vec(nir_alu_instr *instr)
 }
 
 static bool
-is_swizzleless_move(nir_alu_instr *instr)
+is_simple_move(nir_alu_instr *instr)
 {
    if (is_move(instr)) {
+      /* We handle modifiers in a separate pass */
+      if (instr->src[0].negate || instr->src[0].abs)
+         return false;
+
       for (unsigned i = 0; i < 4; i++) {
          if (!((instr->dest.write_mask >> i) & 1))
             break;
@@ -81,6 +80,10 @@ is_swizzleless_move(nir_alu_instr *instr)
          if (instr->src[i].swizzle[0] != i)
             return false;
 
+         /* We handle modifiers in a separate pass */
+         if (instr->src[i].negate || instr->src[i].abs)
+            return false;
+
          if (def == NULL) {
             def = instr->src[i].src.ssa;
          } else if (instr->src[i].src.ssa != def) {
@@ -107,7 +110,7 @@ copy_prop_src(nir_src *src, nir_instr *parent_instr, nir_if *parent_if)
       return false;
 
    nir_alu_instr *alu_instr = nir_instr_as_alu(src_instr);
-   if (!is_swizzleless_move(alu_instr))
+   if (!is_simple_move(alu_instr))
       return false;
 
    /* Don't let copy propagation land us with a phi that has more
-- 
1.9.1