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[C API] Add accessors for new no-wrap flags on GEP instructions (#97970)
Previously, only the inbounds flag was accessible via the C API. This adds support for any no-wrap related flags (currently nuw and nusw).
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‎llvm/docs/ReleaseNotes.rst

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@@ -309,6 +309,14 @@ They are described in detail in the `debug info migration guide <https://llvm.or
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* ``LLVMGetTargetExtTypeNumTypeParams``/``LLVMGetTargetExtTypeTypeParam``
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* ``LLVMGetTargetExtTypeNumIntParams``/``LLVMGetTargetExtTypeIntParam``
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* Added the following functions for accessing/setting the no-wrap flags for a
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GetElementPtr instruction:
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* ``LLVMBuildGEPWithNoWrapFlags``
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* ``LLVMConstGEPWithNoWrapFlags``
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* ``LLVMGEPGetNoWrapFlags``
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* ``LLVMGEPSetNoWrapFlags``
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Changes to the CodeGen infrastructure
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-------------------------------------
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‎llvm/include/llvm-c/Core.h

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@@ -510,6 +510,20 @@ enum {
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*/
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typedef unsigned LLVMFastMathFlags;
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enum {
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LLVMGEPFlagInBounds = (1 << 0),
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LLVMGEPFlagNUSW = (1 << 1),
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LLVMGEPFlagNUW = (1 << 2),
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};
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/**
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* Flags that constrain the allowed wrap semantics of a getelementptr
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* instruction.
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*
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* See https://llvm.org/docs/LangRef.html#getelementptr-instruction
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*/
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typedef unsigned LLVMGEPNoWrapFlags;
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/**
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* @}
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*/
@@ -2395,6 +2409,17 @@ LLVMValueRef LLVMConstGEP2(LLVMTypeRef Ty, LLVMValueRef ConstantVal,
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LLVMValueRef LLVMConstInBoundsGEP2(LLVMTypeRef Ty, LLVMValueRef ConstantVal,
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LLVMValueRef *ConstantIndices,
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unsigned NumIndices);
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/**
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* Creates a constant GetElementPtr expression. Similar to LLVMConstGEP2, but
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* allows specifying the no-wrap flags.
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*
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* @see llvm::ConstantExpr::getGetElementPtr()
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*/
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LLVMValueRef LLVMConstGEPWithNoWrapFlags(LLVMTypeRef Ty,
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LLVMValueRef ConstantVal,
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LLVMValueRef *ConstantIndices,
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unsigned NumIndices,
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LLVMGEPNoWrapFlags NoWrapFlags);
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LLVMValueRef LLVMConstTrunc(LLVMValueRef ConstantVal, LLVMTypeRef ToType);
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LLVMValueRef LLVMConstPtrToInt(LLVMValueRef ConstantVal, LLVMTypeRef ToType);
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LLVMValueRef LLVMConstIntToPtr(LLVMValueRef ConstantVal, LLVMTypeRef ToType);
@@ -3904,6 +3929,20 @@ void LLVMSetIsInBounds(LLVMValueRef GEP, LLVMBool InBounds);
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*/
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LLVMTypeRef LLVMGetGEPSourceElementType(LLVMValueRef GEP);
39063931

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/**
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* Get the no-wrap related flags for the given GEP instruction.
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*
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* @see llvm::GetElementPtrInst::getNoWrapFlags
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*/
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LLVMGEPNoWrapFlags LLVMGEPGetNoWrapFlags(LLVMValueRef GEP);
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/**
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* Set the no-wrap related flags for the given GEP instruction.
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*
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* @see llvm::GetElementPtrInst::setNoWrapFlags
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*/
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void LLVMGEPSetNoWrapFlags(LLVMValueRef GEP, LLVMGEPNoWrapFlags NoWrapFlags);
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39073946
/**
39083947
* @}
39093948
*/
@@ -4363,6 +4402,17 @@ LLVMValueRef LLVMBuildGEP2(LLVMBuilderRef B, LLVMTypeRef Ty,
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LLVMValueRef LLVMBuildInBoundsGEP2(LLVMBuilderRef B, LLVMTypeRef Ty,
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LLVMValueRef Pointer, LLVMValueRef *Indices,
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unsigned NumIndices, const char *Name);
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/**
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* Creates a GetElementPtr instruction. Similar to LLVMBuildGEP2, but allows
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* specifying the no-wrap flags.
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*
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* @see llvm::IRBuilder::CreateGEP()
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*/
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LLVMValueRef LLVMBuildGEPWithNoWrapFlags(LLVMBuilderRef B, LLVMTypeRef Ty,
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LLVMValueRef Pointer,
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LLVMValueRef *Indices,
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unsigned NumIndices, const char *Name,
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LLVMGEPNoWrapFlags NoWrapFlags);
43664416
LLVMValueRef LLVMBuildStructGEP2(LLVMBuilderRef B, LLVMTypeRef Ty,
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LLVMValueRef Pointer, unsigned Idx,
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const char *Name);

‎llvm/lib/IR/Core.cpp

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Original file line numberDiff line numberDiff line change
@@ -1685,6 +1685,32 @@ static int map_from_llvmopcode(LLVMOpcode code)
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llvm_unreachable("Unhandled Opcode.");
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}
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/*-- GEP wrap flag conversions */
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static GEPNoWrapFlags mapFromLLVMGEPNoWrapFlags(LLVMGEPNoWrapFlags GEPFlags) {
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GEPNoWrapFlags NewGEPFlags;
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if ((GEPFlags & LLVMGEPFlagInBounds) != 0)
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NewGEPFlags |= GEPNoWrapFlags::inBounds();
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if ((GEPFlags & LLVMGEPFlagNUSW) != 0)
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NewGEPFlags |= GEPNoWrapFlags::noUnsignedSignedWrap();
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if ((GEPFlags & LLVMGEPFlagNUW) != 0)
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NewGEPFlags |= GEPNoWrapFlags::noUnsignedWrap();
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return NewGEPFlags;
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}
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static LLVMGEPNoWrapFlags mapToLLVMGEPNoWrapFlags(GEPNoWrapFlags GEPFlags) {
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LLVMGEPNoWrapFlags NewGEPFlags = 0;
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if (GEPFlags.isInBounds())
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NewGEPFlags |= LLVMGEPFlagInBounds;
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if (GEPFlags.hasNoUnsignedSignedWrap())
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NewGEPFlags |= LLVMGEPFlagNUSW;
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if (GEPFlags.hasNoUnsignedWrap())
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NewGEPFlags |= LLVMGEPFlagNUW;
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return NewGEPFlags;
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}
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/*--.. Constant expressions ................................................--*/
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LLVMOpcode LLVMGetConstOpcode(LLVMValueRef ConstantVal) {
@@ -1789,6 +1815,18 @@ LLVMValueRef LLVMConstInBoundsGEP2(LLVMTypeRef Ty, LLVMValueRef ConstantVal,
17891815
return wrap(ConstantExpr::getInBoundsGetElementPtr(unwrap(Ty), Val, IdxList));
17901816
}
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LLVMValueRef LLVMConstGEPWithNoWrapFlags(LLVMTypeRef Ty,
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LLVMValueRef ConstantVal,
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LLVMValueRef *ConstantIndices,
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unsigned NumIndices,
1822+
LLVMGEPNoWrapFlags NoWrapFlags) {
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ArrayRef<Constant *> IdxList(unwrap<Constant>(ConstantIndices, NumIndices),
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NumIndices);
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Constant *Val = unwrap<Constant>(ConstantVal);
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return wrap(ConstantExpr::getGetElementPtr(
1827+
unwrap(Ty), Val, IdxList, mapFromLLVMGEPNoWrapFlags(NoWrapFlags)));
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}
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LLVMValueRef LLVMConstTrunc(LLVMValueRef ConstantVal, LLVMTypeRef ToType) {
17931831
return wrap(ConstantExpr::getTrunc(unwrap<Constant>(ConstantVal),
17941832
unwrap(ToType)));
@@ -3102,6 +3140,16 @@ LLVMTypeRef LLVMGetGEPSourceElementType(LLVMValueRef GEP) {
31023140
return wrap(unwrap<GEPOperator>(GEP)->getSourceElementType());
31033141
}
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LLVMGEPNoWrapFlags LLVMGEPGetNoWrapFlags(LLVMValueRef GEP) {
3144+
GEPOperator *GEPOp = unwrap<GEPOperator>(GEP);
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return mapToLLVMGEPNoWrapFlags(GEPOp->getNoWrapFlags());
3146+
}
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3148+
void LLVMGEPSetNoWrapFlags(LLVMValueRef GEP, LLVMGEPNoWrapFlags NoWrapFlags) {
3149+
GetElementPtrInst *GEPInst = unwrap<GetElementPtrInst>(GEP);
3150+
GEPInst->setNoWrapFlags(mapFromLLVMGEPNoWrapFlags(NoWrapFlags));
3151+
}
3152+
31053153
/*--.. Operations on phi nodes .............................................--*/
31063154

31073155
void LLVMAddIncoming(LLVMValueRef PhiNode, LLVMValueRef *IncomingValues,
@@ -3902,6 +3950,16 @@ LLVMValueRef LLVMBuildInBoundsGEP2(LLVMBuilderRef B, LLVMTypeRef Ty,
39023950
unwrap(B)->CreateInBoundsGEP(unwrap(Ty), unwrap(Pointer), IdxList, Name));
39033951
}
39043952

3953+
LLVMValueRef LLVMBuildGEPWithNoWrapFlags(LLVMBuilderRef B, LLVMTypeRef Ty,
3954+
LLVMValueRef Pointer,
3955+
LLVMValueRef *Indices,
3956+
unsigned NumIndices, const char *Name,
3957+
LLVMGEPNoWrapFlags NoWrapFlags) {
3958+
ArrayRef<Value *> IdxList(unwrap(Indices), NumIndices);
3959+
return wrap(unwrap(B)->CreateGEP(unwrap(Ty), unwrap(Pointer), IdxList, Name,
3960+
mapFromLLVMGEPNoWrapFlags(NoWrapFlags)));
3961+
}
3962+
39053963
LLVMValueRef LLVMBuildStructGEP2(LLVMBuilderRef B, LLVMTypeRef Ty,
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LLVMValueRef Pointer, unsigned Idx,
39073965
const char *Name) {

‎llvm/test/Bindings/llvm-c/echo.ll

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@@ -25,6 +25,9 @@ module asm "classical GAS"
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2626
@const_gep = global ptr getelementptr (i32, ptr @var, i64 2)
2727
@const_inbounds_gep = global ptr getelementptr inbounds (i32, ptr @var, i64 1)
28+
@const_gep_nuw = global ptr getelementptr nuw (i32, ptr @var, i64 1)
29+
@const_gep_nusw = global ptr getelementptr nusw (i32, ptr @var, i64 1)
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@const_gep_nuw_inbounds = global ptr getelementptr nuw inbounds (i32, ptr @var, i64 1)
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2932
@aliased1 = alias i32, ptr @var
3033
@aliased2 = internal alias i32, ptr @var
@@ -391,6 +394,15 @@ bb_03:
391394
ret void
392395
}
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397+
define ptr @test_gep_no_wrap_flags(ptr %0) {
398+
%gep.1 = getelementptr i8, ptr %0, i32 4
399+
%gep.inbounds = getelementptr inbounds i8, ptr %0, i32 4
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%gep.nuw = getelementptr nuw i8, ptr %0, i32 4
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%gep.nuw.inbounds = getelementptr inbounds nuw i8, ptr %0, i32 4
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%gep.nusw = getelementptr nusw i8, ptr %0, i32 4
403+
ret ptr %gep.nusw
404+
}
405+
394406
!llvm.dbg.cu = !{!0, !2}
395407
!llvm.module.flags = !{!3}
396408

‎llvm/tools/llvm-c-test/echo.cpp

Lines changed: 7 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -412,10 +412,9 @@ static LLVMValueRef clone_constant_impl(LLVMValueRef Cst, LLVMModuleRef M) {
412412
SmallVector<LLVMValueRef, 8> Idx;
413413
for (int i = 1; i <= NumIdx; i++)
414414
Idx.push_back(clone_constant(LLVMGetOperand(Cst, i), M));
415-
if (LLVMIsInBounds(Cst))
416-
return LLVMConstInBoundsGEP2(ElemTy, Ptr, Idx.data(), NumIdx);
417-
else
418-
return LLVMConstGEP2(ElemTy, Ptr, Idx.data(), NumIdx);
415+
416+
return LLVMConstGEPWithNoWrapFlags(ElemTy, Ptr, Idx.data(), NumIdx,
417+
LLVMGEPGetNoWrapFlags(Cst));
419418
}
420419
default:
421420
fprintf(stderr, "%d is not a supported opcode for constant expressions\n",
@@ -767,11 +766,10 @@ struct FunCloner {
767766
int NumIdx = LLVMGetNumIndices(Src);
768767
for (int i = 1; i <= NumIdx; i++)
769768
Idx.push_back(CloneValue(LLVMGetOperand(Src, i)));
770-
if (LLVMIsInBounds(Src))
771-
Dst = LLVMBuildInBoundsGEP2(Builder, ElemTy, Ptr, Idx.data(), NumIdx,
772-
Name);
773-
else
774-
Dst = LLVMBuildGEP2(Builder, ElemTy, Ptr, Idx.data(), NumIdx, Name);
769+
770+
Dst = LLVMBuildGEPWithNoWrapFlags(Builder, ElemTy, Ptr, Idx.data(),
771+
NumIdx, Name,
772+
LLVMGEPGetNoWrapFlags(Src));
775773
break;
776774
}
777775
case LLVMAtomicRMW: {

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