From 40e9f2f13847ddd94e1216088aa00456d7b02d2b Mon Sep 17 00:00:00 2001 From: Timothy Arceri Date: Tue, 13 Dec 2016 11:37:25 +1100 Subject: [PATCH] i965: disable loop unrolling in GLSL IR There is a single regression in loop unrolling which is: loops HURT: shaders/orbital_explorer.shader_test GS SIMD8: 0 -> 1 However the loop is huge so it seems reasonable not to unroll it. It's surprising that GLSL IR does unroll it. shader-db results BDW: total instructions in shared programs: 13037455 -> 13036947 (-0.00%) instructions in affected programs: 17982 -> 17474 (-2.83%) helped: 63 HURT: 25 total cycles in shared programs: 262217870 -> 262227990 (0.00%) cycles in affected programs: 2287046 -> 2297166 (0.44%) helped: 969 HURT: 844 total loops in shared programs: 2951 -> 2952 (0.03%) loops in affected programs: 0 -> 1 helped: 0 HURT: 1 LOST: 0 GAINED: 1 Reviewed-by: Jason Ekstrand --- src/mesa/drivers/dri/i965/brw_compiler.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/mesa/drivers/dri/i965/brw_compiler.c b/src/mesa/drivers/dri/i965/brw_compiler.c index d7900a7..fa8a772 100644 --- a/src/mesa/drivers/dri/i965/brw_compiler.c +++ b/src/mesa/drivers/dri/i965/brw_compiler.c @@ -122,7 +122,7 @@ brw_compiler_create(void *mem_ctx, const struct gen_device_info *devinfo) /* We want the GLSL compiler to emit code that uses condition codes */ for (int i = 0; i < MESA_SHADER_STAGES; i++) { - compiler->glsl_compiler_options[i].MaxUnrollIterations = 32; + compiler->glsl_compiler_options[i].MaxUnrollIterations = 0; compiler->glsl_compiler_options[i].MaxIfDepth = devinfo->gen < 6 ? 16 : UINT_MAX; -- 2.7.4