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authorEric Anholt <eric@anholt.net>2014-09-16 16:03:39 -0700
committerEric Anholt <eric@anholt.net>2014-09-17 14:21:24 -0700
commit71d4fc88d6b97d6b9a8f1a324d2dcd0c56b79f3d (patch)
treee6e9d5db1fa30689f994c25e02917887b5070407
parent79be2cc383f45e3e1e36e1ab774f2a3ea268cad5 (diff)
vc4: Allow copy propagation of uniforms.
Fixes 12 piglit tests (and 8 more crash -> fail) from reducing register pressure.
-rw-r--r--src/gallium/drivers/vc4/vc4_opt_copy_propagation.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/src/gallium/drivers/vc4/vc4_opt_copy_propagation.c b/src/gallium/drivers/vc4/vc4_opt_copy_propagation.c
index b36bb4209a5..66b7c80a77d 100644
--- a/src/gallium/drivers/vc4/vc4_opt_copy_propagation.c
+++ b/src/gallium/drivers/vc4/vc4_opt_copy_propagation.c
@@ -45,10 +45,22 @@ qir_opt_copy_propagation(struct vc4_compile *c)
foreach(node, &c->instructions) {
struct qinst *inst = (struct qinst *)node;
+ /* A single instruction can only read one uniform value. (It
+ * could maybe read the same uniform value in two operands,
+ * but that doesn't seem important to do).
+ */
+ bool reads_a_uniform = false;
+ for (int i = 0; i < qir_get_op_nsrc(inst->op); i++) {
+ if (inst->src[i].file == QFILE_UNIF)
+ reads_a_uniform = true;
+ }
+
for (int i = 0; i < qir_get_op_nsrc(inst->op); i++) {
int index = inst->src[i].index;
if (inst->src[i].file == QFILE_TEMP &&
- movs[index].file == QFILE_TEMP) {
+ (movs[index].file == QFILE_TEMP ||
+ (movs[index].file == QFILE_UNIF &&
+ !reads_a_uniform))) {
if (debug) {
fprintf(stderr, "Copy propagate: ");
qir_dump_inst(inst);
@@ -56,6 +68,8 @@ qir_opt_copy_propagation(struct vc4_compile *c)
}
inst->src[i] = movs[index];
+ if (movs[index].file == QFILE_UNIF)
+ reads_a_uniform = true;
if (debug) {
fprintf(stderr, "to: ");