Mesa (master): ac/nir: do not emit unnecessary null exports in fragment shaders
Samuel Pitoiset
hakzsam at kemper.freedesktop.org
Thu Mar 8 10:58:08 UTC 2018
Module: Mesa
Branch: master
Commit: 4e3c1ace659c7325bd8d54b66370c3755e40a266
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=4e3c1ace659c7325bd8d54b66370c3755e40a266
Author: Samuel Pitoiset <samuel.pitoiset at gmail.com>
Date: Thu Mar 8 09:53:14 2018 +0100
ac/nir: do not emit unnecessary null exports in fragment shaders
Null exports should only be needed when no other exports are
emitted. This removes a bunch of 'exp null off, off, off, off done vm'.
Affected games are Dota 2 and Wolfenstein 2, not sure if that
really helps, but code size is decreasing there.
Polaris10:
Totals from affected shaders:
SGPRS: 8216 -> 8216 (0.00 %)
VGPRS: 7072 -> 7072 (0.00 %)
Spilled SGPRs: 0 -> 0 (0.00 %)
Spilled VGPRs: 0 -> 0 (0.00 %)
Code Size: 454968 -> 453896 (-0.24 %) bytes
Max Waves: 772 -> 772 (0.00 %)
Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
---
src/amd/common/ac_nir_to_llvm.c | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)
diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
index c785244dcc..9b85069860 100644
--- a/src/amd/common/ac_nir_to_llvm.c
+++ b/src/amd/common/ac_nir_to_llvm.c
@@ -6539,17 +6539,13 @@ handle_tcs_outputs_post(struct radv_shader_context *ctx)
static bool
si_export_mrt_color(struct radv_shader_context *ctx,
- LLVMValueRef *color, unsigned index, bool is_last,
+ LLVMValueRef *color, unsigned index,
struct ac_export_args *args)
{
/* Export */
si_llvm_init_export_args(ctx, color, 0xf,
V_008DFC_SQ_EXP_MRT + index, args);
-
- if (is_last) {
- args->valid_mask = 1; /* whether the EXEC mask is valid */
- args->done = 1; /* DONE bit */
- } else if (!args->enabled_channels)
+ if (!args->enabled_channels)
return false; /* unnecessary NULL export */
return true;
@@ -6576,7 +6572,6 @@ handle_fs_outputs_post(struct radv_shader_context *ctx)
for (unsigned i = 0; i < AC_LLVM_MAX_OUTPUTS; ++i) {
LLVMValueRef values[4];
- bool last = false;
if (!(ctx->output_mask & (1ull << i)))
continue;
@@ -6588,14 +6583,9 @@ handle_fs_outputs_post(struct radv_shader_context *ctx)
values[j] = ac_to_float(&ctx->ac,
radv_load_output(ctx, i, j));
- if (!ctx->shader_info->info.ps.writes_z &&
- !ctx->shader_info->info.ps.writes_stencil &&
- !ctx->shader_info->info.ps.writes_sample_mask)
- last = ctx->output_mask <= ((1ull << (i + 1)) - 1);
-
bool ret = si_export_mrt_color(ctx, values,
i - FRAG_RESULT_DATA0,
- last, &color_args[index]);
+ &color_args[index]);
if (ret)
index++;
}
@@ -6614,6 +6604,19 @@ handle_fs_outputs_post(struct radv_shader_context *ctx)
radv_load_output(ctx, FRAG_RESULT_SAMPLE_MASK, 0));
}
+ /* Set the DONE bit on last non-null color export only if Z isn't
+ * exported.
+ */
+ if (index > 0 &&
+ !ctx->shader_info->info.ps.writes_z &&
+ !ctx->shader_info->info.ps.writes_stencil &&
+ !ctx->shader_info->info.ps.writes_sample_mask) {
+ unsigned last = index - 1;
+
+ color_args[last].valid_mask = 1; /* whether the EXEC mask is valid */
+ color_args[last].done = 1; /* DONE bit */
+ }
+
/* Export PS outputs. */
for (unsigned i = 0; i < index; i++)
ac_build_export(&ctx->ac, &color_args[i]);
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