[llvm] [GlobalISel] Constant-fold G_PTR_ADD with different type sizes (PR #81473)

[Piotr Sobczak via llvm-commits]

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@@ -660,8 +660,15 @@ std::optional<APInt> llvm::ConstantFoldBinOp(unsigned Opcode,
   default:
     break;
   case TargetOpcode::G_ADD:
-  case TargetOpcode::G_PTR_ADD:
     return C1 + C2;
+  case TargetOpcode::G_PTR_ADD: {
+    // Types can be of different width here.
+    if (C1.getBitWidth() < C2.getBitWidth())
+      return C1.zext(C1.getBitWidth()) + C2;
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piotrAMD wrote:

C2.getBitWidth() ?

https://github.com/llvm/llvm-project/pull/81473