[llvm] [NFC][AutoUpgrade] Use `ConstantPointerNull::get` instead of `Constant::getNullValue` for pointer types (PR #139984)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-ir

Author: Shilei Tian (shiltian)

<details>
<summary>Changes</summary>

This is a preparation change for upcoming PRs that will update the semantics of
`ConstantPointerNull`, making it to represent an actual `nullptr` rather than a
zero-valued pointer.

---
Full diff: https://github.com/llvm/llvm-project/pull/139984.diff


1 Files Affected:

- (modified) llvm/lib/IR/AutoUpgrade.cpp (+9-9) 


``````````diff
diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
index 9091e7585f9d9..41aa06add6aba 100644
--- a/llvm/lib/IR/AutoUpgrade.cpp
+++ b/llvm/lib/IR/AutoUpgrade.cpp
@@ -1613,7 +1613,7 @@ GlobalVariable *llvm::UpgradeGlobalVariable(GlobalVariable *GV) {
     auto Ctor = cast<Constant>(Init->getOperand(i));
     NewCtors[i] = ConstantStruct::get(EltTy, Ctor->getAggregateElement(0u),
                                       Ctor->getAggregateElement(1),
-                                      Constant::getNullValue(IRB.getPtrTy()));
+                                      ConstantPointerNull::get(IRB.getPtrTy()));
   }
   Constant *NewInit = ConstantArray::get(ArrayType::get(EltTy, N), NewCtors);
 
@@ -4721,10 +4721,10 @@ void llvm::UpgradeIntrinsicCall(CallBase *CI, Function *NewFn) {
     }
 
     // Create a new call with an added null annotation attribute argument.
-    NewCall =
-        Builder.CreateCall(NewFn, {CI->getArgOperand(0), CI->getArgOperand(1),
-                                   CI->getArgOperand(2), CI->getArgOperand(3),
-                                   Constant::getNullValue(Builder.getPtrTy())});
+    NewCall = Builder.CreateCall(
+        NewFn,
+        {CI->getArgOperand(0), CI->getArgOperand(1), CI->getArgOperand(2),
+         CI->getArgOperand(3), ConstantPointerNull::get(Builder.getPtrTy())});
     NewCall->takeName(CI);
     CI->replaceAllUsesWith(NewCall);
     CI->eraseFromParent();
@@ -4737,10 +4737,10 @@ void llvm::UpgradeIntrinsicCall(CallBase *CI, Function *NewFn) {
       return;
     }
     // Create a new call with an added null annotation attribute argument.
-    NewCall =
-        Builder.CreateCall(NewFn, {CI->getArgOperand(0), CI->getArgOperand(1),
-                                   CI->getArgOperand(2), CI->getArgOperand(3),
-                                   Constant::getNullValue(Builder.getPtrTy())});
+    NewCall = Builder.CreateCall(
+        NewFn,
+        {CI->getArgOperand(0), CI->getArgOperand(1), CI->getArgOperand(2),
+         CI->getArgOperand(3), ConstantPointerNull::get(Builder.getPtrTy())});
     NewCall->takeName(CI);
     CI->replaceAllUsesWith(NewCall);
     CI->eraseFromParent();

``````````

</details>


https://github.com/llvm/llvm-project/pull/139984