Mesa (master): radeonsi: add a workaround for a compute VGPR-usage LLVM bug
Marek Olšák
mareko at kemper.freedesktop.org
Wed Jul 13 17:49:55 UTC 2016
Module: Mesa
Branch: master
Commit: d227dbe2721728c89acc6495bf657cb9fc4d3c69
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=d227dbe2721728c89acc6495bf657cb9fc4d3c69
Author: Marek Olšák <marek.olsak at amd.com>
Date: Sun Jul 3 20:00:17 2016 +0200
radeonsi: add a workaround for a compute VGPR-usage LLVM bug
v2: use abort(), describe which LLVM version is affected
Cc: 12.0 <mesa-stable at lists.freedesktop.org>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle at amd.com>
---
src/gallium/drivers/radeonsi/si_shader.c | 35 ++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index c7ecb7e..64fbd74 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -6697,6 +6697,41 @@ int si_compile_tgsi_shader(struct si_screen *sscreen,
radeon_llvm_dispose(&ctx.radeon_bld);
+ /* Validate SGPR and VGPR usage for compute to detect compiler bugs.
+ * LLVM 3.9svn has this bug.
+ */
+ if (sel->type == PIPE_SHADER_COMPUTE) {
+ unsigned *props = sel->info.properties;
+ unsigned wave_size = 64;
+ unsigned max_vgprs = 256;
+ unsigned max_sgprs = sscreen->b.chip_class >= VI ? 800 : 512;
+ unsigned max_sgprs_per_wave = 128;
+ unsigned min_waves_per_cu =
+ DIV_ROUND_UP(props[TGSI_PROPERTY_CS_FIXED_BLOCK_WIDTH] *
+ props[TGSI_PROPERTY_CS_FIXED_BLOCK_HEIGHT] *
+ props[TGSI_PROPERTY_CS_FIXED_BLOCK_DEPTH],
+ wave_size);
+ unsigned min_waves_per_simd = DIV_ROUND_UP(min_waves_per_cu, 4);
+
+ max_vgprs = max_vgprs / min_waves_per_simd;
+ max_sgprs = MIN2(max_sgprs / min_waves_per_simd, max_sgprs_per_wave);
+
+ if (shader->config.num_sgprs > max_sgprs ||
+ shader->config.num_vgprs > max_vgprs) {
+ fprintf(stderr, "LLVM failed to compile a shader correctly: "
+ "SGPR:VGPR usage is %u:%u, but the hw limit is %u:%u\n",
+ shader->config.num_sgprs, shader->config.num_vgprs,
+ max_sgprs, max_vgprs);
+
+ /* Just terminate the process, because dependent
+ * shaders can hang due to bad input data, but use
+ * the env var to allow shader-db to work.
+ */
+ if (!debug_get_bool_option("SI_PASS_BAD_SHADERS", false))
+ abort();
+ }
+ }
+
/* Add the scratch offset to input SGPRs. */
if (shader->config.scratch_bytes_per_wave)
shader->info.num_input_sgprs += 1; /* scratch byte offset */
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