[Mesa-dev] [PATCH 3/4] radeonsi: create load_const_buffer_desc_fast_path() helper

[Timothy Arceri]

This will be shared by the TGSI and NIR backends. For simplicity
we leave the SI LLVM 5.0 and lower work around only in the TGSI
backend.
---
 src/gallium/drivers/radeonsi/si_shader.c | 88 ++++++++++++++++++--------------
 1 file changed, 49 insertions(+), 39 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index d5607a99d32..62cb7ea7eb5 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -2322,6 +2322,49 @@ void si_tgsi_declare_compute_memory(struct si_shader_context *ctx,
 	si_declare_compute_memory(ctx);
 }
 
+static LLVMValueRef load_const_buffer_desc_fast_path(struct si_shader_context *ctx)
+{
+	LLVMValueRef ptr =
+		LLVMGetParam(ctx->main_fn, ctx->param_const_and_shader_buffers);
+	struct si_shader_selector *sel = ctx->shader->selector;
+
+	/* Do the bounds checking with a descriptor, because
+	 * doing computation and manual bounds checking of 64-bit
+	 * addresses generates horrible VALU code with very high
+	 * VGPR usage and very low SIMD occupancy.
+	 */
+	ptr = LLVMBuildPtrToInt(ctx->ac.builder, ptr, ctx->ac.intptr, "");
+
+	LLVMValueRef desc0, desc1;
+	if (HAVE_32BIT_POINTERS) {
+		desc0 = ptr;
+		desc1 = LLVMConstInt(ctx->i32,
+				     S_008F04_BASE_ADDRESS_HI(ctx->screen->info.address32_hi), 0);
+	} else {
+		ptr = LLVMBuildBitCast(ctx->ac.builder, ptr, ctx->v2i32, "");
+		desc0 = LLVMBuildExtractElement(ctx->ac.builder, ptr, ctx->i32_0, "");
+		desc1 = LLVMBuildExtractElement(ctx->ac.builder, ptr, ctx->i32_1, "");
+		/* Mask out all bits except BASE_ADDRESS_HI. */
+		desc1 = LLVMBuildAnd(ctx->ac.builder, desc1,
+				     LLVMConstInt(ctx->i32, ~C_008F04_BASE_ADDRESS_HI, 0), "");
+	}
+
+	LLVMValueRef desc_elems[] = {
+		desc0,
+		desc1,
+		LLVMConstInt(ctx->i32, (sel->info.const_file_max[0] + 1) * 16, 0),
+		LLVMConstInt(ctx->i32,
+			S_008F0C_DST_SEL_X(V_008F0C_SQ_SEL_X) |
+			S_008F0C_DST_SEL_Y(V_008F0C_SQ_SEL_Y) |
+			S_008F0C_DST_SEL_Z(V_008F0C_SQ_SEL_Z) |
+			S_008F0C_DST_SEL_W(V_008F0C_SQ_SEL_W) |
+			S_008F0C_NUM_FORMAT(V_008F0C_BUF_NUM_FORMAT_FLOAT) |
+			S_008F0C_DATA_FORMAT(V_008F0C_BUF_DATA_FORMAT_32), 0)
+	};
+
+	return ac_build_gather_values(&ctx->ac, desc_elems, 4);
+}
+
 static LLVMValueRef load_const_buffer_desc(struct si_shader_context *ctx, int i)
 {
 	LLVMValueRef list_ptr = LLVMGetParam(ctx->main_fn,
@@ -2400,8 +2443,6 @@ static LLVMValueRef fetch_constant(
 	/* Fast path when user data SGPRs point to constant buffer 0 directly. */
 	if (sel->info.const_buffers_declared == 1 &&
 	    sel->info.shader_buffers_declared == 0) {
-		LLVMValueRef ptr =
-			LLVMGetParam(ctx->main_fn, ctx->param_const_and_shader_buffers);
 
 		/* This enables use of s_load_dword and flat_load_dword for const buffer 0
 		 * loads, and up to x4 load opcode merging. However, it leads to horrible
@@ -2416,48 +2457,17 @@ static LLVMValueRef fetch_constant(
 		 * s_buffer_load_dword (that we have to prevent) is when we use use
 		 * a literal offset where we don't need bounds checking.
 		 */
-		if (ctx->screen->info.chip_class == SI &&
-                    HAVE_LLVM < 0x0600 &&
-                    !reg->Register.Indirect) {
+		if (ctx->screen->info.chip_class == SI && HAVE_LLVM < 0x0600 &&
+		    !reg->Register.Indirect) {
+			LLVMValueRef ptr =
+				LLVMGetParam(ctx->main_fn, ctx->param_const_and_shader_buffers);
+
 			addr = LLVMBuildLShr(ctx->ac.builder, addr, LLVMConstInt(ctx->i32, 2, 0), "");
 			LLVMValueRef result = ac_build_load_invariant(&ctx->ac, ptr, addr);
 			return bitcast(bld_base, type, result);
 		}
 
-		/* Do the bounds checking with a descriptor, because
-		 * doing computation and manual bounds checking of 64-bit
-		 * addresses generates horrible VALU code with very high
-		 * VGPR usage and very low SIMD occupancy.
-		 */
-		ptr = LLVMBuildPtrToInt(ctx->ac.builder, ptr, ctx->ac.intptr, "");
-
-		LLVMValueRef desc0, desc1;
-		if (HAVE_32BIT_POINTERS) {
-			desc0 = ptr;
-			desc1 = LLVMConstInt(ctx->i32,
-					     S_008F04_BASE_ADDRESS_HI(ctx->screen->info.address32_hi), 0);
-		} else {
-			ptr = LLVMBuildBitCast(ctx->ac.builder, ptr, ctx->v2i32, "");
-			desc0 = LLVMBuildExtractElement(ctx->ac.builder, ptr, ctx->i32_0, "");
-			desc1 = LLVMBuildExtractElement(ctx->ac.builder, ptr, ctx->i32_1, "");
-			/* Mask out all bits except BASE_ADDRESS_HI. */
-			desc1 = LLVMBuildAnd(ctx->ac.builder, desc1,
-					     LLVMConstInt(ctx->i32, ~C_008F04_BASE_ADDRESS_HI, 0), "");
-		}
-
-		LLVMValueRef desc_elems[] = {
-			desc0,
-			desc1,
-			LLVMConstInt(ctx->i32, (sel->info.const_file_max[0] + 1) * 16, 0),
-			LLVMConstInt(ctx->i32,
-				S_008F0C_DST_SEL_X(V_008F0C_SQ_SEL_X) |
-				S_008F0C_DST_SEL_Y(V_008F0C_SQ_SEL_Y) |
-				S_008F0C_DST_SEL_Z(V_008F0C_SQ_SEL_Z) |
-				S_008F0C_DST_SEL_W(V_008F0C_SQ_SEL_W) |
-				S_008F0C_NUM_FORMAT(V_008F0C_BUF_NUM_FORMAT_FLOAT) |
-				S_008F0C_DATA_FORMAT(V_008F0C_BUF_DATA_FORMAT_32), 0)
-		};
-		LLVMValueRef desc = ac_build_gather_values(&ctx->ac, desc_elems, 4);
+		LLVMValueRef desc = load_const_buffer_desc_fast_path(ctx);
 		LLVMValueRef result = buffer_load_const(ctx, desc, addr);
 		return bitcast(bld_base, type, result);
 	}
-- 
2.14.3