From 22f9fbc0d94bcf19c7ec58ccbd2036df2cf03514 Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Wed, 13 Jun 2018 15:07:41 -0700 Subject: [PATCH] i965/vec4: Optimize OR with 0 into a MOV MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit All of the affected shaders are geometry shaders... the same ones from the similar fs changes. The "No changes on any other platforms" comment below is not quite right. Without the previous change to register coalescing, this optimization caused quite a few regressions in tests that either used gl_ClipVertex or used different interpolation modes. I observed that with both patches applied, glsl-1.10/execution/interpolation/interpolation-none-gl_BackSecondaryColor-smooth-vertex.shader_test was one instruction shorter. I suspect other shaders would be similarly affected. Since this is all based on NOS, shader-db does not reflect it. Haswell total instructions in shared programs: 12954955 -> 12954918 (<.01%) instructions in affected programs: 3603 -> 3566 (-1.03%) helped: 37 HURT: 0 helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 helped stats (rel) min: 0.21% max: 2.50% x̄: 1.99% x̃: 2.50% 95% mean confidence interval for instructions value: -1.00 -1.00 95% mean confidence interval for instructions %-change: -2.30% -1.69% Instructions are helped. total cycles in shared programs: 410012108 -> 410012098 (<.01%) cycles in affected programs: 3540 -> 3530 (-0.28%) helped: 5 HURT: 0 helped stats (abs) min: 2 max: 2 x̄: 2.00 x̃: 2 helped stats (rel) min: 0.28% max: 0.28% x̄: 0.28% x̃: 0.28% 95% mean confidence interval for cycles value: -2.00 -2.00 95% mean confidence interval for cycles %-change: -0.28% -0.28% Cycles are helped. Ivy Bridge total instructions in shared programs: 11679387 -> 11679351 (<.01%) instructions in affected programs: 3292 -> 3256 (-1.09%) helped: 36 HURT: 0 helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 helped stats (rel) min: 0.21% max: 2.50% x̄: 2.04% x̃: 2.50% 95% mean confidence interval for instructions value: -1.00 -1.00 95% mean confidence interval for instructions %-change: -2.34% -1.74% Instructions are helped. No changes on any other platforms. Signed-off-by: Ian Romanick --- src/intel/compiler/brw_vec4.cpp | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/intel/compiler/brw_vec4.cpp b/src/intel/compiler/brw_vec4.cpp index e67d7802550..d1c46d610d9 100644 --- a/src/intel/compiler/brw_vec4.cpp +++ b/src/intel/compiler/brw_vec4.cpp @@ -810,6 +810,14 @@ vec4_visitor::opt_algebraic() } break; + case BRW_OPCODE_OR: + if (inst->src[1].is_zero()) { + inst->opcode = BRW_OPCODE_MOV; + inst->src[1] = src_reg(); + progress = true; + } + break; + case VEC4_OPCODE_UNPACK_UNIFORM: if (inst->src[0].file != UNIFORM) { inst->opcode = BRW_OPCODE_MOV; -- 2.11.0