Module: Mesa
Branch: master
Commit: ed5af9437344f932f8cbebfa776f873d16a8aae1
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=ed5af9437344f932f8cbebfa776f873d16a8aae1
Author: Matt Turner <matts...@gmail.com>
Date: Thu Apr 26 21:25:42 2018 -0700
nir: Transform discard_if(true) into discard
Noticed while reviewing Tim Arceri's NIR inlining series.
Without his series:
instructions in affected programs: 16 -> 14 (-12.50%)
helped: 2
With his series:
instructions in affected programs: 196 -> 174 (-11.22%)
helped: 22
Reviewed-by: Jason Ekstrand <ja...@jlekstrand.net>
---
src/compiler/nir/nir_opt_constant_folding.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/src/compiler/nir/nir_opt_constant_folding.c
b/src/compiler/nir/nir_opt_constant_folding.c
index a848b14587..fe34f4ade8 100644
--- a/src/compiler/nir/nir_opt_constant_folding.c
+++ b/src/compiler/nir/nir_opt_constant_folding.c
@@ -167,7 +167,22 @@ constant_fold_intrinsic_instr(nir_intrinsic_instr *instr)
if (instr->intrinsic == nir_intrinsic_discard_if) {
nir_const_value *src_val = nir_src_as_const_value(instr->src[0]);
- if (src_val && src_val->u32[0] == 0) {
+ if (src_val && src_val->u32[0] == NIR_FALSE) {
+ nir_instr_remove(&instr->instr);
+ progress = true;
+ } else if (src_val && src_val->u32[0] == NIR_TRUE) {
+ /* This method of getting a nir_shader * from a nir_instr is
+ * admittedly gross, but given the rarity of hitting this case I think
+ * it's preferable to plumbing an otherwise unused nir_shader *
+ * parameter through four functions to get here.
+ */
+ nir_cf_node *cf_node = &instr->instr.block->cf_node;
+ nir_function_impl *impl = nir_cf_node_get_function(cf_node);
+ nir_shader *shader = impl->function->shader;
+
+ nir_intrinsic_instr *discard =
+ nir_intrinsic_instr_create(shader, nir_intrinsic_discard);
+ nir_instr_insert_before(&instr->instr, &discard->instr);
nir_instr_remove(&instr->instr);
progress = true;
}
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