radeonsi: use slot indexes for bindless handles

Using VRAM address as bindless handles is not a good idea because
we have to use LLVMIntToPTr and the LLVM CSE pass can't optimize
because it has no information about the pointer.

Instead, use slots indexes like the existing descriptors. Note
that we use fixed 16-dword slots for both samplers and images.
This doesn't really matter because no real apps use image handles.

This improves performance with DOW3 by +7%.

Signed-off-by: Samuel Pitoiset <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>

1 files changed, 20 insertions, 15 deletions

diff --git a/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c b/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c
index f8c99ff7e77..1e44b68b860 100644
--- a/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c
+++ b/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c
@@ -205,15 +205,22 @@ image_fetch_rsrc(
 	}
 
 	if (image->Register.File != TGSI_FILE_IMAGE) {
+		/* Bindless descriptors are accessible from a different pair of
+		 * user SGPR indices.
+		 */
 		struct gallivm_state *gallivm = &ctx->gallivm;
 		LLVMBuilderRef builder = gallivm->builder;
 
-		LLVMValueRef ptr =
-			lp_build_emit_fetch_src(bld_base, image,
-						TGSI_TYPE_UNSIGNED64, 0);
-		rsrc_ptr = LLVMBuildIntToPtr(builder, ptr,
-					     si_const_array(ctx->v8i32, 0), "");
-		index = LLVMConstInt(ctx->i32, 0, 0);
+		rsrc_ptr = LLVMGetParam(ctx->main_fn,
+					ctx->param_bindless_samplers_and_images);
+		index = lp_build_emit_fetch_src(bld_base, image,
+						TGSI_TYPE_UNSIGNED, 0);
+
+		/* For simplicity, bindless image descriptors use fixed
+		 * 16-dword slots for now.
+		 */
+		index = LLVMBuildMul(builder, index,
+				     LLVMConstInt(ctx->i32, 2, 0), "");
 	}
 
 	*rsrc = si_load_image_desc(ctx, rsrc_ptr, index,
@@ -1213,15 +1220,13 @@ static void tex_fetch_ptrs(
 	}
 
 	if (reg->Register.File != TGSI_FILE_SAMPLER) {
-		struct gallivm_state *gallivm = &ctx->gallivm;
-		LLVMBuilderRef builder = gallivm->builder;
-
-		LLVMValueRef ptr =
-			lp_build_emit_fetch_src(bld_base, reg,
-						TGSI_TYPE_UNSIGNED64, 0);
-		list = LLVMBuildIntToPtr(builder, ptr,
-					 si_const_array(ctx->v8i32, 0), "");
-		index = LLVMConstInt(ctx->i32, 0, 0);
+		/* Bindless descriptors are accessible from a different pair of
+		 * user SGPR indices.
+		 */
+		list = LLVMGetParam(ctx->main_fn,
+				    ctx->param_bindless_samplers_and_images);
+		index = lp_build_emit_fetch_src(bld_base, reg,
+						TGSI_TYPE_UNSIGNED, 0);
 	}
 
 	if (target == TGSI_TEXTURE_BUFFER)