[llvm] [SPIRV] Handle ptrcast between array and vector types (PR #166418)

[Steven Perron via llvm-commits]

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@@ -116,6 +116,85 @@ class SPIRVLegalizePointerCast : public FunctionPass {
     return LI;
   }
 
+  // Loads elements from an array and constructs a vector.
+  Value *loadVectorFromArray(IRBuilder<> &B, FixedVectorType *TargetType,
+                             ArrayType *SourceType, Value *Source) {
+    // Ensure the element types of the array and vector are the same.
+    assert(TargetType->getElementType() == SourceType->getElementType() &&
+           "Element types of array and vector must be the same.");
+
+    // Load each element of the array.
+    SmallVector<Value *, 4> LoadedElements;
+    for (unsigned i = 0; i < TargetType->getNumElements(); ++i) {
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s-perron wrote:

In bounds or not is a parameter to spv_gep.

If the target type has more elements, then we get an out-of-bounds access with undefined behaviour. However, the original access would have had undefined behaviour anyway.

https://github.com/llvm/llvm-project/pull/166418