[llvm] [InstCombine] Move alignment assumptions to the base of constant offset GEPs (PR #204602)

[Nikolas Klauser via llvm-commits]

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@@ -3686,6 +3686,15 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
           return RemoveBundle();
         }
 
+        Value *BasePtr;
+        uint64_t PtrOffset;
+        if (match(Ptr.get(),
+                  m_PtrAdd(m_Value(BasePtr), m_ConstantInt(PtrOffset)))) {
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philnik777 wrote:

It seems that constants in GEPs always get sign-extended, so I don't think that's observable?

https://github.com/llvm/llvm-project/pull/204602