[clang] [llvm] [IR] Add ConstantExpr::getInBoundsPtrAdd() (PR #181639)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-ir

Author: Nikita Popov (nikic)

<details>
<summary>Changes</summary>

As a followup to https://github.com/llvm/llvm-project/pull/181365, this adds the `getInBoundsPtrAdd()` variant and updates code to use it.

---
Full diff: https://github.com/llvm/llvm-project/pull/181639.diff


5 Files Affected:

- (modified) clang/lib/CodeGen/ItaniumCXXABI.cpp (+1-2) 
- (modified) llvm/include/llvm/IR/Constants.h (+5) 
- (modified) llvm/lib/Transforms/IPO/LowerTypeTests.cpp (+2-5) 
- (modified) llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp (+2-2) 
- (modified) llvm/unittests/Transforms/Utils/CallPromotionUtilsTest.cpp (+2-2) 


``````````diff
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 759e512ed0719..c62bc4998c324 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -4074,8 +4074,7 @@ void ItaniumRTTIBuilder::BuildVTablePointer(const Type *Ty,
     // The vtable address point is 8 bytes after its start:
     // 4 for the offset to top + 4 for the relative offset to rtti.
     llvm::Constant *Eight = llvm::ConstantInt::get(CGM.Int32Ty, 8);
-    VTable =
-        llvm::ConstantExpr::getInBoundsGetElementPtr(CGM.Int8Ty, VTable, Eight);
+    VTable = llvm::ConstantExpr::getInBoundsPtrAdd(VTable, Eight);
   } else {
     llvm::Constant *Two = llvm::ConstantInt::get(PtrDiffTy, 2);
     VTable = llvm::ConstantExpr::getInBoundsGetElementPtr(CGM.GlobalsInt8PtrTy,
diff --git a/llvm/include/llvm/IR/Constants.h b/llvm/include/llvm/IR/Constants.h
index b31490f9ca660..a1f667353b26e 100644
--- a/llvm/include/llvm/IR/Constants.h
+++ b/llvm/include/llvm/IR/Constants.h
@@ -1334,6 +1334,11 @@ class ConstantExpr : public Constant {
     return getGetElementPtr(Ty, C, IdxList, GEPNoWrapFlags::inBounds());
   }
 
+  /// Create a getelementptr inbounds i8, ptr, offset constant expression.
+  static Constant *getInBoundsPtrAdd(Constant *Ptr, Constant *Offset) {
+    return getPtrAdd(Ptr, Offset, GEPNoWrapFlags::inBounds());
+  }
+
   LLVM_ABI static Constant *getExtractElement(Constant *Vec, Constant *Idx,
                                               Type *OnlyIfReducedTy = nullptr);
   LLVM_ABI static Constant *getInsertElement(Constant *Vec, Constant *Elt,
diff --git a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
index c2b39754ba5df..518e91628a478 100644
--- a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
+++ b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
@@ -644,11 +644,8 @@ void LowerTypeTestsModule::allocateByteArrays() {
 
   for (unsigned I = 0; I != ByteArrayInfos.size(); ++I) {
     ByteArrayInfo *BAI = &ByteArrayInfos[I];
-
-    Constant *Idxs[] = {ConstantInt::get(IntPtrTy, 0),
-                        ConstantInt::get(IntPtrTy, ByteArrayOffsets[I])};
-    Constant *GEP = ConstantExpr::getInBoundsGetElementPtr(
-        ByteArrayConst->getType(), ByteArray, Idxs);
+    Constant *GEP = ConstantExpr::getInBoundsPtrAdd(
+        ByteArray, ConstantInt::get(IntPtrTy, ByteArrayOffsets[I]));
 
     // Create an alias instead of RAUW'ing the gep directly. On x86 this ensures
     // that the pc-relative displacement is folded into the lea instead of the
diff --git a/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp b/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
index 48131955836b3..f3cdb3518ddcb 100644
--- a/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
+++ b/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
@@ -216,8 +216,8 @@ static Constant *getVTableAddressPointOffset(GlobalVariable *VTable,
   assert(AddressPointOffset < VTable->getGlobalSize(M.getDataLayout()) &&
          "Out-of-bound access");
 
-  return ConstantExpr::getInBoundsGetElementPtr(
-      Type::getInt8Ty(Context), VTable,
+  return ConstantExpr::getInBoundsPtrAdd(
+      VTable,
       llvm::ConstantInt::get(Type::getInt32Ty(Context), AddressPointOffset));
 }
 
diff --git a/llvm/unittests/Transforms/Utils/CallPromotionUtilsTest.cpp b/llvm/unittests/Transforms/Utils/CallPromotionUtilsTest.cpp
index 59c047afd84df..c859b0c799f08 100644
--- a/llvm/unittests/Transforms/Utils/CallPromotionUtilsTest.cpp
+++ b/llvm/unittests/Transforms/Utils/CallPromotionUtilsTest.cpp
@@ -43,8 +43,8 @@ static Constant *getVTableAddressPointOffset(GlobalVariable *VTable,
              M.getDataLayout().getTypeAllocSize(VTable->getValueType()) &&
          "Out-of-bound access");
 
-  return ConstantExpr::getInBoundsGetElementPtr(
-      Type::getInt8Ty(Context), VTable,
+  return ConstantExpr::getInBoundsPtrAdd(
+      VTable,
       llvm::ConstantInt::get(Type::getInt32Ty(Context), AddressPointOffset));
 }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/181639