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-rw-r--r--src/compiler/nir/nir_opt_remove_phis.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/src/compiler/nir/nir_opt_remove_phis.c b/src/compiler/nir/nir_opt_remove_phis.c
index ee92fbefacb..acaa6e1911c 100644
--- a/src/compiler/nir/nir_opt_remove_phis.c
+++ b/src/compiler/nir/nir_opt_remove_phis.c
@@ -26,6 +26,7 @@
*/
#include "nir.h"
+#include "nir_builder.h"
static nir_alu_instr *
get_parent_mov(nir_ssa_def *ssa)
@@ -63,7 +64,7 @@ matching_mov(nir_alu_instr *mov1, nir_ssa_def *ssa)
*/
static bool
-remove_phis_block(nir_block *block)
+remove_phis_block(nir_block *block, nir_builder *b)
{
bool progress = false;
@@ -113,6 +114,21 @@ remove_phis_block(nir_block *block)
*/
assert(def != NULL);
+ if (mov) {
+ /* If the sources were all mov's from the same source with the same
+ * swizzle, then we can't just pick a random move because it may not
+ * dominate the phi node. Instead, we need to emit our own move after
+ * the phi which uses the shared source, and rewrite uses of the phi
+ * to use the move instead. This is ok, because while the mov's may
+ * not all dominate the phi node, their shared source does.
+ */
+
+ b->cursor = nir_after_phis(block);
+ def = mov->op == nir_op_imov ?
+ nir_imov_alu(b, mov->src[0], def->num_components) :
+ nir_fmov_alu(b, mov->src[0], def->num_components);
+ }
+
assert(phi->dest.is_ssa);
nir_ssa_def_rewrite_uses(&phi->dest.ssa, nir_src_for_ssa(def));
nir_instr_remove(instr);
@@ -127,9 +143,11 @@ static bool
remove_phis_impl(nir_function_impl *impl)
{
bool progress = false;
+ nir_builder bld;
+ nir_builder_init(&bld, impl);
nir_foreach_block(block, impl) {
- progress |= remove_phis_block(block);
+ progress |= remove_phis_block(block, &bld);
}
if (progress) {