From 1aa8a0392f256a1be8f8d2774a4f7d3e03b3aac3 Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Tue, 15 Mar 2016 18:32:19 -0700 Subject: [PATCH] nir: Optimize out discard_ifs with a constant 0 argument. I found this in a shader that was doing an alpha test when alpha is fixed at 1.0. v2: Rebase on master (now the const value is "u32" not "u"). Reviewed-by: Jason Ekstrand (v1) --- src/compiler/nir/nir_opt_constant_folding.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/compiler/nir/nir_opt_constant_folding.c b/src/compiler/nir/nir_opt_constant_folding.c index 8f04061..d6be807 100644 --- a/src/compiler/nir/nir_opt_constant_folding.c +++ b/src/compiler/nir/nir_opt_constant_folding.c @@ -155,6 +155,14 @@ constant_fold_intrinsic_instr(nir_intrinsic_instr *instr) progress |= constant_fold_deref(&instr->instr, instr->variables[i]); } + 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) { + nir_instr_remove(&instr->instr); + progress = true; + } + } + return progress; } -- 2.7.4