Commit 74470bae authored by Connor Abbott's avatar Connor Abbott

ac/nir: Lower large indirect variables to scratch

results from radeonsi NIR:

Totals from affected shaders:
SGPRS: 704 -> 464 (-34.09 %)
VGPRS: 2056 -> 672 (-67.32 %)
Spilled SGPRs: 24 -> 0 (-100.00 %)
Spilled VGPRs: 28406 -> 0 (-100.00 %)
Private memory VGPRs: 0 -> 3182 (0.00 %)
Scratch size: 1064 -> 3228 (203.38 %) dwords per thread
Code Size: 935260 -> 40180 (-95.70 %) bytes
LDS: 0 -> 0 (0.00 %) blocks
Max Waves: 28 -> 70 (150.00 %)
Wait states: 0 -> 0 (0.00 %)

results from radv:

Totals from affected shaders:
SGPRS: 80 -> 48 (-40.00 %)
VGPRS: 204 -> 108 (-47.06 %)
Spilled SGPRs: 0 -> 0 (0.00 %)
Spilled VGPRs: 0 -> 0 (0.00 %)
Private memory VGPRs: 0 -> 0 (0.00 %)
Scratch size: 0 -> 256 (0.00 %) dwords per thread
Code Size: 15792 -> 9504 (-39.82 %) bytes
LDS: 0 -> 0 (0.00 %) blocks
Max Waves: 1 -> 2 (100.00 %)
Wait states: 0 -> 0 (0.00 %)
Reviewed-by: Bas Nieuwenhuizen's avatarBas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
parent 3c9144f9
Pipeline #53516 passed with stages
in 8 minutes and 51 seconds
......@@ -42,6 +42,8 @@ struct ac_nir_context {
LLVMValueRef *ssa_defs;
LLVMValueRef scratch;
struct hash_table *defs;
struct hash_table *phis;
struct hash_table *vars;
......@@ -3573,6 +3575,36 @@ static void visit_intrinsic(struct ac_nir_context *ctx,
case nir_intrinsic_mbcnt_amd:
result = ac_build_mbcnt(&ctx->ac, get_src(ctx, instr->src[0]));
break;
case nir_intrinsic_load_scratch: {
LLVMValueRef offset = get_src(ctx, instr->src[0]);
LLVMValueRef ptr = ac_build_gep0(&ctx->ac, ctx->scratch,
offset);
LLVMTypeRef comp_type =
LLVMIntTypeInContext(ctx->ac.context, instr->dest.ssa.bit_size);
LLVMTypeRef vec_type =
instr->dest.ssa.num_components == 1 ? comp_type :
LLVMVectorType(comp_type, instr->dest.ssa.num_components);
unsigned addr_space = LLVMGetPointerAddressSpace(LLVMTypeOf(ptr));
ptr = LLVMBuildBitCast(ctx->ac.builder, ptr,
LLVMPointerType(vec_type, addr_space), "");
result = LLVMBuildLoad(ctx->ac.builder, ptr, "");
break;
}
case nir_intrinsic_store_scratch: {
LLVMValueRef offset = get_src(ctx, instr->src[1]);
LLVMValueRef ptr = ac_build_gep0(&ctx->ac, ctx->scratch,
offset);
LLVMTypeRef comp_type =
LLVMIntTypeInContext(ctx->ac.context, instr->src[0].ssa->bit_size);
LLVMTypeRef vec_type =
instr->src[0].ssa->num_components == 1 ? comp_type :
LLVMVectorType(comp_type, instr->src[0].ssa->num_components);
unsigned addr_space = LLVMGetPointerAddressSpace(LLVMTypeOf(ptr));
ptr = LLVMBuildBitCast(ctx->ac.builder, ptr,
LLVMPointerType(vec_type, addr_space), "");
LLVMBuildStore(ctx->ac.builder, get_src(ctx, instr->src[0]), ptr);
break;
}
default:
fprintf(stderr, "Unknown intrinsic: ");
nir_print_instr(&instr->instr, stderr);
......@@ -4473,6 +4505,18 @@ setup_locals(struct ac_nir_context *ctx,
}
}
static void
setup_scratch(struct ac_nir_context *ctx,
struct nir_shader *shader)
{
if (shader->scratch_size == 0)
return;
ctx->scratch = ac_build_alloca_undef(&ctx->ac,
LLVMArrayType(ctx->ac.i8, shader->scratch_size),
"scratch");
}
static void
setup_shared(struct ac_nir_context *ctx,
struct nir_shader *nir)
......@@ -4518,6 +4562,7 @@ void ac_nir_translate(struct ac_llvm_context *ac, struct ac_shader_abi *abi,
ctx.ssa_defs = calloc(func->impl->ssa_alloc, sizeof(LLVMValueRef));
setup_locals(&ctx, func);
setup_scratch(&ctx, nir);
if (gl_shader_stage_is_compute(nir->info.stage))
setup_shared(&ctx, nir);
......@@ -4539,6 +4584,15 @@ void ac_nir_translate(struct ac_llvm_context *ac, struct ac_shader_abi *abi,
void
ac_lower_indirect_derefs(struct nir_shader *nir, enum chip_class chip_class)
{
/* Lower large variables to scratch first so that we won't bloat the
* shader by generating large if ladders for them. We later lower
* scratch to alloca's, assuming LLVM won't generate VGPR indexing.
*/
NIR_PASS_V(nir, nir_lower_vars_to_scratch,
nir_var_function_temp,
256,
glsl_get_natural_size_align_bytes);
/* While it would be nice not to have this flag, we are constrained
* by the reality that LLVM 9.0 has buggy VGPR indexing on GFX9.
*/
......
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