[llvm] SimplifyLibCalls: Use the correct address space when computing integer widths. (PR #118586)

[Owen Anderson via llvm-commits]

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@@ -590,26 +588,35 @@ Value *LibCallSimplifier::optimizeStrCmp(CallInst *CI, IRBuilderBase &B) {
   if (Len1 && Len2) {
     return copyFlags(
         *CI, emitMemCmp(Str1P, Str2P,
-                        ConstantInt::get(DL.getIntPtrType(CI->getContext()),
-                                         std::min(Len1, Len2)),
+                        ConstantInt::get(
+                            DL.getIntPtrType(
+                                CI->getContext(),
+                                Str1P->getType()->getPointerAddressSpace()),
+                            std::min(Len1, Len2)),
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resistor wrote:

> The reason getSizeTSize() unconditionally queries addrspace(0) is just that there aren't any in-tree targets where it needs to return anything else. Fixes welcome.

Honestly, I don't think fixing `getSizeTSize()` makes sense. It's just a wrapper around `DataLayout::getPointerSizeInBits`, which is already more widely accessible throughout the middle-end than `TargetLibraryInfo` is.

If we really want the convenience name, then I think we should move `getSizeTSize` to `DataLayout`, and add an addrspace argument such that it is a pure wrapper around `getPointerSizeInBits`.

https://github.com/llvm/llvm-project/pull/118586