[llvm] 8baa212 - [DirectX] Handle <1 x ...> loads in DXILResourceAccess (#137076)

[via llvm-commits]

Author: Justin Bogner
Date: 2025-04-24T14:17:11-06:00
New Revision: 8baa212b7aef800a0f7d9abad529a3976bef9d50

URL: https://github.com/llvm/llvm-project/commit/8baa212b7aef800a0f7d9abad529a3976bef9d50
DIFF: https://github.com/llvm/llvm-project/commit/8baa212b7aef800a0f7d9abad529a3976bef9d50.diff

LOG: [DirectX] Handle <1 x ...> loads in DXILResourceAccess (#137076)

We can end up with loads of single element vectors when we have scalar
values, because the vectorizer may introduce these to use ops like
shufflevector in some cases. Make sure we're maintaining the correct
type when translating these into resource load operations.

Fixes #136409.

Added: 
    

Modified: 
    llvm/lib/Target/DirectX/DXILResourceAccess.cpp
    llvm/test/CodeGen/DirectX/ResourceAccess/load_typedbuffer.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/DirectX/DXILResourceAccess.cpp b/llvm/lib/Target/DirectX/DXILResourceAccess.cpp
index 3b8f7140d3122..16337f1237e00 100644
--- a/llvm/lib/Target/DirectX/DXILResourceAccess.cpp
+++ b/llvm/lib/Target/DirectX/DXILResourceAccess.cpp
@@ -143,6 +143,13 @@ static void createTypedBufferLoad(IntrinsicInst *II, LoadInst *LI,
   if (Offset)
     V = Builder.CreateExtractElement(V, Offset);
 
+  // If we loaded a <1 x ...> instead of a scalar (presumably to feed a
+  // shufflevector), then make sure we're maintaining the resulting type.
+  if (auto *VT = dyn_cast<FixedVectorType>(LI->getType()))
+    if (VT->getNumElements() == 1 && !isa<FixedVectorType>(V->getType()))
+      V = Builder.CreateInsertElement(PoisonValue::get(VT), V,
+                                      Builder.getInt32(0));
+
   LI->replaceAllUsesWith(V);
 }
 

diff  --git a/llvm/test/CodeGen/DirectX/ResourceAccess/load_typedbuffer.ll b/llvm/test/CodeGen/DirectX/ResourceAccess/load_typedbuffer.ll
index 8769e6ec66d8e..b51b9ae4b4a11 100644
--- a/llvm/test/CodeGen/DirectX/ResourceAccess/load_typedbuffer.ll
+++ b/llvm/test/CodeGen/DirectX/ResourceAccess/load_typedbuffer.ll
@@ -4,8 +4,9 @@ target triple = "dxil-pc-shadermodel6.6-compute"
 
 declare void @use_float4(<4 x float>)
 declare void @use_float(float)
+declare void @use_float1(<1 x float>)
 
-; CHECK-LABEL: define void @load_float4
+; CHECK-LABEL: define void @load_float4(
 define void @load_float4(i32 %index, i32 %elemindex) {
   %buffer = call target("dx.TypedBuffer", <4 x float>, 1, 0, 0)
       @llvm.dx.resource.handlefrombinding.tdx.TypedBuffer_v4f32_1_0_0(
@@ -35,3 +36,48 @@ define void @load_float4(i32 %index, i32 %elemindex) {
 
   ret void
 }
+
+; CHECK-LABEL: define void @load_float(
+define void @load_float(i32 %index) {
+  %buffer = call target("dx.TypedBuffer", float, 1, 0, 0)
+      @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+
+  ; CHECK-NOT: @llvm.dx.resource.getpointer
+  %ptr = call ptr @llvm.dx.resource.getpointer(
+      target("dx.TypedBuffer", float, 1, 0, 0) %buffer, i32 %index)
+
+  ; CHECK: %[[LOAD:.*]] = call { float, i1 } @llvm.dx.resource.load.typedbuffer.f32.tdx.TypedBuffer_f32_1_0_0t(target("dx.TypedBuffer", float, 1, 0, 0) %buffer, i32 %index)
+  ; CHECK: %[[VALUE:.*]] = extractvalue { float, i1 } %[[LOAD]], 0
+  ; CHECK: call void @use_float(float %[[VALUE]])
+  %data = load float, ptr %ptr
+  call void @use_float(float %data)
+
+  ; CHECK: %[[LOAD:.*]] = call { float, i1 } @llvm.dx.resource.load.typedbuffer.f32.tdx.TypedBuffer_f32_1_0_0t(target("dx.TypedBuffer", float, 1, 0, 0) %buffer, i32 %index)
+  ; CHECK: %[[VALUE:.*]] = extractvalue { float, i1 } %[[LOAD]], 0
+  ; CHECK: %[[VEC:.*]] = insertelement <1 x float> poison, float %[[VALUE]], i32 0
+  ; CHECK: call void @use_float1(<1 x float> %[[VEC]])
+  %vec_data = load <1 x float>, ptr %ptr
+  call void @use_float1(<1 x float> %vec_data)
+
+  ret void
+}
+
+; CHECK-LABEL: define void @load_float1(
+define void @load_float1(i32 %index) {
+  %buffer = call target("dx.TypedBuffer", <1 x float>, 1, 0, 0)
+      @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+
+  ; CHECK-NOT: @llvm.dx.resource.getpointer
+  %ptr = call ptr @llvm.dx.resource.getpointer(
+      target("dx.TypedBuffer", <1 x float>, 1, 0, 0) %buffer, i32 %index)
+
+  ; CHECK: %[[LOAD:.*]] = call { <1 x float>, i1 } @llvm.dx.resource.load.typedbuffer.v1f32.tdx.TypedBuffer_v1f32_1_0_0t(target("dx.TypedBuffer", <1 x float>, 1, 0, 0) %buffer, i32 %index)
+  ; CHECK: %[[VALUE:.*]] = extractvalue { <1 x float>, i1 } %[[LOAD]], 0
+  ; CHECK: %[[SHUF:.*]] = shufflevector <1 x float> %[[VALUE]], <1 x float> poison, <4 x i32> zeroinitializer
+  ; CHECK: call void @use_float4(<4 x float> %[[SHUF]])
+  %load = load <1 x float>, ptr %ptr
+  %shuf = shufflevector <1 x float> %load, <1 x float> poison, <4 x i32> zeroinitializer
+  call void @use_float4(<4 x float> %shuf)
+
+  ret void
+}