radeonsi: don't preload constants at the beginning of shaders
LLVM can CSE the loads, thus we can always re-load constants before each
use. The decrease in SGPR spilling is huge.
The best improvements are the dumbest ones.
26011 shaders in 14651 tests
Totals:
SGPRS: 1453346 -> 1251920 (-13.86 %)
VGPRS: 742576 -> 728421 (-1.91 %)
Spilled SGPRs: 52298 -> 16644 (-68.17 %)
Spilled VGPRs: 397 -> 369 (-7.05 %)
Scratch VGPRs: 1372 -> 1344 (-2.04 %) dwords per thread
Code Size: 36136488 -> 36001064 (-0.37 %) bytes
LDS: 767 -> 767 (0.00 %) blocks
Max Waves: 219315 -> 222221 (1.33 %)
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 0b7de18..6801722 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -107,7 +107,6 @@
LLVMValueRef const_buffers[SI_NUM_CONST_BUFFERS];
LLVMValueRef lds;
- LLVMValueRef *constants[SI_NUM_CONST_BUFFERS];
LLVMValueRef shader_buffers[SI_NUM_SHADER_BUFFERS];
LLVMValueRef sampler_views[SI_NUM_SAMPLERS];
LLVMValueRef sampler_states[SI_NUM_SAMPLERS];
@@ -1881,12 +1880,19 @@
idx = reg->Register.Index * 4 + swizzle;
if (!reg->Register.Indirect && !reg->Dimension.Indirect) {
+ LLVMValueRef c0, c1;
+
+ c0 = buffer_load_const(ctx, ctx->const_buffers[buf],
+ LLVMConstInt(ctx->i32, idx * 4, 0));
+
if (!tgsi_type_is_64bit(type))
- return bitcast(bld_base, type, ctx->constants[buf][idx]);
+ return bitcast(bld_base, type, c0);
else {
+ c1 = buffer_load_const(ctx, ctx->const_buffers[buf],
+ LLVMConstInt(ctx->i32,
+ (idx + 1) * 4, 0));
return radeon_llvm_emit_fetch_64bit(bld_base, type,
- ctx->constants[buf][idx],
- ctx->constants[buf][idx + 1]);
+ c0, c1);
}
}
@@ -5796,25 +5802,12 @@
LLVMValueRef ptr = LLVMGetParam(ctx->radeon_bld.main_fn, SI_PARAM_CONST_BUFFERS);
for (buf = 0; buf < SI_NUM_CONST_BUFFERS; buf++) {
- unsigned i, num_const = info->const_file_max[buf] + 1;
-
- if (num_const == 0)
+ if (info->const_file_max[buf] == -1)
continue;
- /* Allocate space for the constant values */
- ctx->constants[buf] = CALLOC(num_const * 4, sizeof(LLVMValueRef));
-
/* Load the resource descriptor */
ctx->const_buffers[buf] =
build_indexed_load_const(ctx, ptr, lp_build_const_int32(gallivm, buf));
-
- /* Load the constants, we rely on the code sinking to do the rest */
- for (i = 0; i < num_const * 4; ++i) {
- ctx->constants[buf][i] =
- buffer_load_const(ctx,
- ctx->const_buffers[buf],
- lp_build_const_int32(gallivm, i * 4));
- }
}
}
@@ -6905,8 +6898,6 @@
}
out:
- for (int i = 0; i < SI_NUM_CONST_BUFFERS; i++)
- FREE(ctx.constants[i]);
return r;
}