[llvm] [SeparateConstOffsetFromGEP] Decompose constant xor operand if possible (PR #135788)

[Juan Manuel Martinez Caamaño via llvm-commits]

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@@ -1162,6 +1167,179 @@ bool SeparateConstOffsetFromGEP::splitGEP(GetElementPtrInst *GEP) {
   return true;
 }
 
+bool SeparateConstOffsetFromGEP::decomposeXor(Function &F) {
+  bool FunctionChanged = false;
+  SmallVector<std::pair<Instruction *, Value *>, 16> ReplacementsToMake;
+
+  for (BasicBlock &BB : F) {
+    for (Instruction &I : BB) {
+      if (I.getOpcode() == Instruction::Xor) {
+        if (Value *Replacement = tryFoldXorToOrDisjoint(I)) {
+          ReplacementsToMake.push_back({&I, Replacement});
+          FunctionChanged = true;
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jmmartinez wrote:

We don't need `FunctionChanged`, just check if `!ReplacementsToMake.empty()`

https://github.com/llvm/llvm-project/pull/135788