Attachment 84544 Details for Bug 68224 – LLVM Patch #3

[patch] LLVM Patch #3

0003-radeonsi-Don-t-preload-constants.patch (text/plain), 3.69 KB, created by Tom Stellard on 2013-08-24 00:19:46 UTC

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Creator: Tom Stellard

Created: 2013-08-24 00:19:46 UTC

Size: 3.69 KB

patch

obsolete

>From 301bd70ef0b947154c4b39f8c4e434625ff271ac Mon Sep 17 00:00:00 2001
>From: Tom Stellard <thomas.stellard@amd.com>
>Date: Fri, 23 Aug 2013 16:13:29 -0400
>Subject: [PATCH 3/3] radeonsi: Don't preload constants
>
>Preloading constants was som shader to run out of SGPRs, because the
>shader compiler was not being aggressive enough when sinking
>instructions into successor blocks.
>---
> src/gallium/drivers/radeonsi/radeonsi_shader.c | 58 ++++++++++++--------------
> 1 file changed, 27 insertions(+), 31 deletions(-)
>
>diff --git a/src/gallium/drivers/radeonsi/radeonsi_shader.c b/src/gallium/drivers/radeonsi/radeonsi_shader.c
>index 775d04f..843d3ad 100644
>--- a/src/gallium/drivers/radeonsi/radeonsi_shader.c
>+++ b/src/gallium/drivers/radeonsi/radeonsi_shader.c
>@@ -457,8 +457,22 @@ static LLVMValueRef fetch_constant(
> 	}
> 
> 	idx = reg->Register.Index * 4 + swizzle;
>-	if (!reg->Register.Indirect)
>-		return bitcast(bld_base, type, si_shader_ctx->constants[idx]);
>+	if (!reg->Register.Indirect) {
>+		/* We cannot cache the constant values and must re-emit them
>+		 * for every use.  Otherwise we may generate invalid code
>+		 * if the cached constant first appears in a basic block that
>+		 * does not dominate its successors.  For example:
>+		 * A
>+		 * | \
>+		 * |  B : Constant loaded
>+                 * | /
>+		 * C : Constant used
>+		 */
>+		LLVMValueRef c = build_constant_load(si_shader_ctx,
>+			si_shader_ctx->const_resource,
>+			lp_build_const_int32(bld_base->base.gallivm, 4 * idx));
>+		return bitcast(bld_base, type, c);
>+	}
> 
> 	addr = si_shader_ctx->radeon_bld.soa.addr[ireg->Index][ireg->Swizzle];
> 	addr = LLVMBuildLoad(base->gallivm->builder, addr, "load addr reg");
>@@ -1421,34 +1435,6 @@ static void create_function(struct si_shader_context *si_shader_ctx)
> #endif
> }
> 
>-static void preload_constants(struct si_shader_context *si_shader_ctx)
>-{
>-	struct lp_build_tgsi_context * bld_base = &si_shader_ctx->radeon_bld.soa.bld_base;
>-	struct gallivm_state * gallivm = bld_base->base.gallivm;
>-	const struct tgsi_shader_info * info = bld_base->info;
>-
>-	unsigned i, num_const = info->file_max[TGSI_FILE_CONSTANT] + 1;
>-
>-	LLVMValueRef ptr;
>-
>-	if (num_const == 0)
>-		return;
>-
>-	/* Allocate space for the constant values */
>-	si_shader_ctx->constants = CALLOC(num_const * 4, sizeof(LLVMValueRef));
>-
>-	/* Load the resource descriptor */
>-	ptr = LLVMGetParam(si_shader_ctx->radeon_bld.main_fn, SI_PARAM_CONST);
>-	si_shader_ctx->const_resource = build_indexed_load(si_shader_ctx, ptr, bld_base->uint_bld.zero);
>-
>-	/* Load the constants, we rely on the code sinking to do the rest */
>-	for (i = 0; i < num_const * 4; ++i) {
>-		si_shader_ctx->constants[i] = build_constant_load(si_shader_ctx,
>-					si_shader_ctx->const_resource,
>-					lp_build_const_int32(gallivm, i * 4));
>-	}
>-}
>-
> static void preload_samplers(struct si_shader_context *si_shader_ctx)
> {
> 	struct lp_build_tgsi_context * bld_base = &si_shader_ctx->radeon_bld.soa.bld_base;
>@@ -1588,6 +1574,7 @@ int si_pipe_shader_create(
> 	LLVMModuleRef mod;
> 	bool dump;
> 	int r = 0;
>+	LLVMValueRef ptr;
> 
> 	dump = debug_get_bool_option("RADEON_DUMP_SHADERS", FALSE);
> 
>@@ -1631,7 +1618,16 @@ int si_pipe_shader_create(
> 
> 	create_meta_data(&si_shader_ctx);
> 	create_function(&si_shader_ctx);
>-	preload_constants(&si_shader_ctx);
>+	/* Allocate space for the constant values */
>+	si_shader_ctx.constants = CALLOC(
>+		4 * (shader_info.file_max[TGSI_FILE_CONSTANT] + 1),
>+		sizeof(LLVMValueRef));
>+
>+	/* Load the resource descriptor */
>+	ptr = LLVMGetParam(si_shader_ctx.radeon_bld.main_fn, SI_PARAM_CONST);
>+	si_shader_ctx.const_resource = build_indexed_load(&si_shader_ctx, ptr,
>+						bld_base->uint_bld.zero);
>+
> 	preload_samplers(&si_shader_ctx);
> 
> 	shader->shader.nr_cbufs = rctx->framebuffer.nr_cbufs;
>-- 
>1.8.1.5
>

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