---
src/compiler/nir/nir_opt_move_comparisons.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/src/compiler/nir/nir_opt_move_comparisons.c
b/src/compiler/nir/nir_opt_move_comparisons.c
index 2bfd940..617c2ca 100644
--- a/src/compiler/nir/nir_opt_move_comparisons.c
+++ b/src/compiler/nir/nir_opt_move_comparisons.c
@@ -84,8 +84,7 @@ move_comparison_source(nir_src *src, nir_block *block,
nir_instr *before)
if (src_instr->block == block &&
src_instr->type == nir_instr_type_alu &&
- is_comparison(nir_instr_as_alu(src_instr)->op) &&
- (!before || before->type != nir_instr_type_phi)) {
+ is_comparison(nir_instr_as_alu(src_instr)->op)) {
exec_node_remove(&src_instr->node);
@@ -135,7 +134,18 @@ move_comparisons(nir_block *block)
}
nir_foreach_instr_reverse(instr, block) {
- if (instr->type == nir_instr_type_alu) {
+ /* The sources of phi instructions happen after the predecessor block
+ * but before this block. (Yes, that's between blocks). This means
+ * that we don't need to move them in order for them to be correct.
+ * We could move them to encourage comparisons that are used in a phi to
+ * the end of the block, doing so correctly would make the pass
+ * substantially more complicated and wouldn't gain us anything since
+ * the phi can't use a flag value anyway.
+ */
+ if (instr->type == nir_instr_type_phi) {
+ /* We're going backwards so everything else is a phi too */
+ break;
+ } else if (instr->type == nir_instr_type_alu) {
/* Walk ALU instruction sources backwards so that bcsel's boolean
* condition is processed last.
*/
--
2.5.0.400.gff86faf
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