Reviewed-by: Bas Nieuwenhuizen <b...@basnieuwenhuizen.nl>
On Sat, Sep 10, 2016 at 12:40 AM, Marek Olšák <mar...@gmail.com> wrote:
> From: Marek Olšák <marek.ol...@amd.com>
>
> 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 %)
> ---
> src/gallium/drivers/radeonsi/si_shader.c | 30 +++++++++++-------------------
> 1 file changed, 11 insertions(+), 19 deletions(-)
>
> diff --git a/src/gallium/drivers/radeonsi/si_shader.c
> b/src/gallium/drivers/radeonsi/si_shader.c
> index 0b7de18..08e3cee 100644
> --- a/src/gallium/drivers/radeonsi/si_shader.c
> +++ b/src/gallium/drivers/radeonsi/si_shader.c
> @@ -1874,26 +1874,33 @@ static LLVMValueRef fetch_constant(
> for (chan = 0; chan < TGSI_NUM_CHANNELS; ++chan)
> values[chan] = fetch_constant(bld_base, reg, type,
> chan);
>
> return lp_build_gather_values(bld_base->base.gallivm, values,
> 4);
> }
>
> buf = reg->Register.Dimension ? reg->Dimension.Index : 0;
> 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);
> }
> }
>
> if (reg->Register.Dimension && reg->Dimension.Indirect) {
> LLVMValueRef ptr = LLVMGetParam(ctx->radeon_bld.main_fn,
> SI_PARAM_CONST_BUFFERS);
> LLVMValueRef index;
> index = get_bounded_indirect_index(ctx, ®->DimIndirect,
> reg->Dimension.Index,
> SI_NUM_CONST_BUFFERS);
> bufp = build_indexed_load_const(ctx, ptr, index);
> @@ -5789,39 +5796,26 @@ static void create_function(struct si_shader_context
> *ctx)
>
> static void preload_constants(struct si_shader_context *ctx)
> {
> struct lp_build_tgsi_context *bld_base =
> &ctx->radeon_bld.soa.bld_base;
> struct gallivm_state *gallivm = bld_base->base.gallivm;
> const struct tgsi_shader_info *info = bld_base->info;
> unsigned buf;
> 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));
> - }
> }
> }
>
> static void preload_shader_buffers(struct si_shader_context *ctx)
> {
> struct gallivm_state *gallivm = &ctx->radeon_bld.gallivm;
> LLVMValueRef ptr = LLVMGetParam(ctx->radeon_bld.main_fn,
> SI_PARAM_SHADER_BUFFERS);
> int buf, maxbuf;
>
> maxbuf = MIN2(ctx->shader->selector->info.file_max[TGSI_FILE_BUFFER],
> @@ -6898,22 +6892,20 @@ int si_compile_tgsi_shader(struct si_screen *sscreen,
> ctx.shader = shader->gs_copy_shader;
> if ((r = si_generate_gs_copy_shader(sscreen, &ctx,
> shader, debug))) {
> free(shader->gs_copy_shader);
> shader->gs_copy_shader = NULL;
> goto out;
> }
> }
>
> out:
> - for (int i = 0; i < SI_NUM_CONST_BUFFERS; i++)
> - FREE(ctx.constants[i]);
> return r;
> }
>
> /**
> * Create, compile and return a shader part (prolog or epilog).
> *
> * \param sscreen screen
> * \param list list of shader parts of the same category
> * \param key shader part key
> * \param tm LLVM target machine
> --
> 2.7.4
>
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