[llvm] [IR] Add TargetExtType::CanBeLocal property (PR #99016)

[Jay Foad via llvm-commits]

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@@ -838,12 +838,14 @@ static TargetTypeInfo getTargetTypeInfo(const TargetExtType *Ty) {
     return TargetTypeInfo(PointerType::get(C, 0), TargetExtType::CanBeGlobal);
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jayfoad wrote:

There are now some tests which do use spirv.Image in allocas:
```
test/CodeGen/SPIRV/transcoding/image_with_access_qualifiers.ll
test/CodeGen/SPIRV/transcoding/get_image_num_mip_levels.ll
test/CodeGen/SPIRV/image-unoptimized.ll
test/CodeGen/SPIRV/read_image.ll
```
@jcranmer-intel any comments on the validity of this? Is it a supported use of spirv.Image, or just something that was conventient for these test cases?

https://github.com/llvm/llvm-project/pull/99016