Previously the last stage would not get optimised until the backend did
its GLSL IR opt loop. I plan on removing that from i965 shortly which
caused huge regressions in Deus-ex and Tomb Raider which have large
constant arrays. Moving lowering before the opt loop in the GLSL linker
fixes this and unexpectedly improves some compute shaders also.
shader-db results BDW:
instructions helped:
shaders/closed/steam/deus-ex-mankind-divided/374.shader_test CS SIMD16: 204 ->
194 (-4.90%)
instructions helped:
shaders/closed/steam/deus-ex-mankind-divided/318.shader_test CS SIMD8: 1010 ->
741 (-26.63%)
instructions helped:
shaders/closed/steam/deus-ex-mankind-divided/144.shader_test CS SIMD8: 542 ->
385 (-28.97%)
cycles helped: shaders/closed/steam/deus-ex-mankind-divided/318.shader_test
CS SIMD8: 1831382 -> 1818492 (-0.70%)
cycles helped: shaders/closed/steam/deus-ex-mankind-divided/144.shader_test
CS SIMD8: 216238 -> 206180 (-4.65%)
cycles helped: shaders/closed/steam/deus-ex-mankind-divided/374.shader_test
CS SIMD16: 18484 -> 16644 (-9.95%)
total instructions in shared programs: 13060313 -> 13059877 (-0.00%)
instructions in affected programs: 1756 -> 1320 (-24.83%)
helped: 3
HURT: 0
total cycles in shared programs: 256586698 -> 256561910 (-0.01%)
cycles in affected programs: 2066104 -> 2041316 (-1.20%)
helped: 3
HURT: 0
V2: call opts before and after lowering (Suggested by Ken)
---
src/compiler/glsl/linker.cpp | 38 ++++++++++++++++++++++++++------------
1 file changed, 26 insertions(+), 12 deletions(-)
diff --git a/src/compiler/glsl/linker.cpp b/src/compiler/glsl/linker.cpp
index d187b66..3d50963 100644
--- a/src/compiler/glsl/linker.cpp
+++ b/src/compiler/glsl/linker.cpp
@@ -4761,6 +4761,24 @@ link_varyings_and_uniforms(unsigned first, unsigned last,
return true;
}
+static void
+linker_optimisation_loop(struct gl_context *ctx, exec_list *ir,
+ unsigned stage)
+{
+ if (ctx->Const.GLSLOptimizeConservatively) {
+ /* Run it just once. */
+ do_common_optimization(ir, true, false,
+ &ctx->Const.ShaderCompilerOptions[stage],
+ ctx->Const.NativeIntegers);
+ } else {
+ /* Repeat it until it stops making changes. */
+ while (do_common_optimization(ir, true, false,
+
&ctx->Const.ShaderCompilerOptions[stage],
+ ctx->Const.NativeIntegers))
+ ;
+ }
+}
+
void
link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
{
@@ -5051,20 +5069,16 @@ link_shaders(struct gl_context *ctx, struct
gl_shader_program *prog)
lower_tess_level(prog->_LinkedShaders[i]);
}
- if (ctx->Const.GLSLOptimizeConservatively) {
- /* Run it just once. */
- do_common_optimization(prog->_LinkedShaders[i]->ir, true, false,
- &ctx->Const.ShaderCompilerOptions[i],
- ctx->Const.NativeIntegers);
- } else {
- /* Repeat it until it stops making changes. */
- while (do_common_optimization(prog->_LinkedShaders[i]->ir, true,
false,
- &ctx->Const.ShaderCompilerOptions[i],
- ctx->Const.NativeIntegers))
- ;
- }
+ /* Call opts before lowering const arrays to uniforms so we can const
+ * propagate any elements accessed directly.
+ */
+ linker_optimisation_loop(ctx, prog->_LinkedShaders[i]->ir, i);
lower_const_arrays_to_uniforms(prog->_LinkedShaders[i]->ir, i);
+
+ /* Call opts after lowering const arrays to copy propagate things. */
+ linker_optimisation_loop(ctx, prog->_LinkedShaders[i]->ir, i);
+
propagate_invariance(prog->_LinkedShaders[i]->ir);
}
--
2.9.3
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