[llvm] [FPEnv][AtomicExpand] Correct strictfp attribute handling in AtomicExpandPass (PR #87082)

[Matt Arsenault via llvm-commits]

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@@ -135,10 +135,14 @@ class AtomicExpandLegacy : public FunctionPass {
 // IRBuilder to be used for replacement atomic instructions.
 struct ReplacementIRBuilder : IRBuilder<InstSimplifyFolder> {
   // Preserves the DebugLoc from I, and preserves still valid metadata.
+  // Enable StrictFP builder mode when appropriate.
   explicit ReplacementIRBuilder(Instruction *I, const DataLayout &DL)
       : IRBuilder(I->getContext(), DL) {
     SetInsertPoint(I);
     this->CollectMetadataToCopy(I, {LLVMContext::MD_pcsections});
+    if (I->getParent()->getParent()->getAttributes().hasFnAttr(
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arsenm wrote:

```suggestion
    if (BB->getParent()->getAttributes().hasFnAttr(
```

https://github.com/llvm/llvm-project/pull/87082