[SPIRV] Preserve bitcast implicit bitcast

Author: farzonl

llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp

@@ -74,17 +74,17 @@ class SPIRVLegalizePointerCast : public FunctionPass {
   // Returns the loaded value.
   Value *loadVectorFromVector(IRBuilder<> &B, FixedVectorType *SourceType,
                               FixedVectorType *TargetType, Value *Source) {
-    // We expect the codegen to avoid doing implicit bitcast from a load.
-    assert(TargetType->getElementType() == SourceType->getElementType());
-    assert(TargetType->getNumElements() < SourceType->getNumElements());
-
+    assert(TargetType->getNumElements() <= SourceType->getNumElements());
     LoadInst *NewLoad = B.CreateLoad(SourceType, Source);
-    buildAssignType(B, SourceType, NewLoad);
+    Value *AssignType = NewLoad;
+    if (TargetType->getElementType() != SourceType->getElementType())
+      AssignType = B.CreateBitCast(NewLoad, TargetType);
+    buildAssignType(B, SourceType, AssignType);
 
     SmallVector<int> Mask(/* Size= */ TargetType->getNumElements());
     for (unsigned I = 0; I < TargetType->getNumElements(); ++I)
       Mask[I] = I;
-    Value *Output = B.CreateShuffleVector(NewLoad, NewLoad, Mask);
+    Value *Output = B.CreateShuffleVector(AssignType, AssignType, Mask);
     buildAssignType(B, TargetType, Output);
     return Output;
   }

llvm/test/CodeGen/SPIRV/hlsl-resources/issue-146942-ptr-cast.ll

@@ -0,0 +1,24 @@
+; RUN: llc -O0 -verify-machineinstrs -mtriple=spirv-unknown-vulkan %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-vulkan %s -o - -filetype=obj | spirv-val %}
+
+@.str = private unnamed_addr constant [4 x i8] c"In3\00", align 1
+@.str.2 = private unnamed_addr constant [5 x i8] c"Out3\00", align 1
+
+; Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(readwrite, inaccessiblemem: none)
+define void @main() local_unnamed_addr #0 {
+  ; CHECK: %[[#INT32:]] = OpTypeInt 32 0
+  ; CHECK: %[[#INT4:]] = OpTypeVector %[[#INT32]] 4
+  ; CHECK: %[[#FLOAT:]] = OpTypeFloat 32
+  ; CHECK: %[[#FLOAT4:]] = OpTypeVector %[[#FLOAT]] 4
+  ; CHECK: %[[#BUFFER_LOAD:]] = OpLoad %[[#FLOAT4]] %{{[0-9]+}} Aligned 16
+  ; CHECK: %[[#VEC_SHUFFLE:]] = OpVectorShuffle %[[#INT4]] %[[#BUFFER_LOAD]] %[[#BUFFER_LOAD]] 0 1 2 3
+  %1 = tail call target("spirv.VulkanBuffer", [0 x <4 x float>], 12, 0) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_a0v4f32_12_0t(i32 0, i32 2, i32 1, i32 0, i1 false, ptr nonnull @.str)
+  %2 = tail call target("spirv.VulkanBuffer", [0 x <4 x i32>], 12, 1) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_a0v4i32_12_1t(i32 0, i32 5, i32 1, i32 0, i1 false, ptr nonnull @.str.2)
+  %3 = tail call noundef align 16 dereferenceable(16) ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.VulkanBuffer_a0v4f32_12_0t(target("spirv.VulkanBuffer", [0 x <4 x float>], 12, 0) %1, i32 0)
+  %4 = load <4 x i32>, ptr addrspace(11) %3, align 16
+  %5 = tail call noundef align 16 dereferenceable(16) ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.VulkanBuffer_a0v4i32_12_1t(target("spirv.VulkanBuffer", [0 x <4 x i32>], 12, 1) %2, i32 0)
+  store <4 x i32> %4, ptr addrspace(11) %5, align 16
+  ret void
+}
+
+attributes #0 = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(readwrite, inaccessiblemem: none) "approx-func-fp-math"="true" "frame-pointer"="all" "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" "no-infs-fp-math"="true" "no-nans-fp-math"="true" "no-signed-zeros-fp-math"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }