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[LLVM][IR] When evaluating GEP offsets don't assume ConstantInt is a scalar. #117162

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Merged
merged 1 commit into from
Dec 4, 2024
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[LLVM][IR] When evaluating GEP offsets don't assume ConstantInt is a scalar. #117162

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2 changes: 1 addition & 1 deletion llvm/lib/Analysis/ConstantFolding.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -881,7 +881,7 @@ Constant *SymbolicallyEvaluateGEP(const GEPOperator *GEP,
Type *IntIdxTy = DL.getIndexType(Ptr->getType());

for (unsigned i = 1, e = Ops.size(); i != e; ++i)
if (!isa<ConstantInt>(Ops[i]))
if (!isa<ConstantInt>(Ops[i]) || !Ops[i]->getType()->isIntegerTy())
return nullptr;

unsigned BitWidth = DL.getTypeSizeInBits(IntIdxTy);
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9 changes: 6 additions & 3 deletions llvm/lib/IR/Operator.cpp
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Expand Up @@ -126,7 +126,8 @@ bool GEPOperator::accumulateConstantOffset(
APInt &Offset, function_ref<bool(Value &, APInt &)> ExternalAnalysis) {
// Fast path for canonical getelementptr i8 form.
if (SourceType->isIntegerTy(8) && !ExternalAnalysis) {
if (auto *CI = dyn_cast<ConstantInt>(Index.front())) {
auto *CI = dyn_cast<ConstantInt>(Index.front());
if (CI && CI->getType()->isIntegerTy()) {
Offset += CI->getValue().sextOrTrunc(Offset.getBitWidth());
return true;
}
Expand Down Expand Up @@ -163,7 +164,8 @@ bool GEPOperator::accumulateConstantOffset(
Value *V = GTI.getOperand();
StructType *STy = GTI.getStructTypeOrNull();
// Handle ConstantInt if possible.
if (auto ConstOffset = dyn_cast<ConstantInt>(V)) {
auto *ConstOffset = dyn_cast<ConstantInt>(V);
if (ConstOffset && ConstOffset->getType()->isIntegerTy()) {
if (ConstOffset->isZero())
continue;
// if the type is scalable and the constant is not zero (vscale * n * 0 =
Expand Down Expand Up @@ -222,7 +224,8 @@ bool GEPOperator::collectOffset(
Value *V = GTI.getOperand();
StructType *STy = GTI.getStructTypeOrNull();
// Handle ConstantInt if possible.
if (auto ConstOffset = dyn_cast<ConstantInt>(V)) {
auto *ConstOffset = dyn_cast<ConstantInt>(V);
if (ConstOffset && ConstOffset->getType()->isIntegerTy()) {
if (ConstOffset->isZero())
continue;
// If the type is scalable and the constant is not zero (vscale * n * 0 =
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9 changes: 9 additions & 0 deletions llvm/test/Transforms/GVN/opaque-ptr.ll
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@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -passes=gvn < %s | FileCheck %s
; RUN: opt -S -passes=gvn -use-constant-int-for-fixed-length-splat < %s | FileCheck %s

declare void @use(ptr)
declare void @use.i32(i32)
Expand Down Expand Up @@ -58,6 +59,10 @@ define void @gep_cse_offset_canonicalization(ptr %p, i64 %idx, i64 %idx2) {
; CHECK-NEXT: call void @use(ptr [[GEP6]])
; CHECK-NEXT: call void @use(ptr [[GEP6_SAME]])
; CHECK-NEXT: call void @use(ptr [[GEP6_DIFFERENT]])
; CHECK-NEXT: %gep7 = getelementptr <16 x i32>, ptr %p, i64 1
; CHECK-NEXT: %gep7.different = getelementptr <16 x i32>, ptr %p, <16 x i64> splat (i64 1)
; CHECK-NEXT: call void @use(ptr %gep7)
; CHECK-NEXT: call void @use(<16 x ptr> %gep7.different)
; CHECK-NEXT: ret void
;
%gep1 = getelementptr i64, ptr %p, i64 1
Expand Down Expand Up @@ -101,6 +106,10 @@ define void @gep_cse_offset_canonicalization(ptr %p, i64 %idx, i64 %idx2) {
call void @use(ptr %gep6)
call void @use(ptr %gep6.same)
call void @use(ptr %gep6.different)
%gep7 = getelementptr <16 x i32>, ptr %p, i64 1
%gep7.different = getelementptr <16 x i32>, ptr %p, <16 x i64> splat (i64 1)
call void @use(ptr %gep7)
call void @use(<16 x ptr> %gep7.different)
ret void
}

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1 change: 1 addition & 0 deletions llvm/test/Transforms/InstCombine/gep-vector-indices.ll
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@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -passes=instcombine %s -S | FileCheck %s
; RUN: opt -passes=instcombine -use-constant-int-for-fixed-length-splat %s -S | FileCheck %s

define ptr @vector_splat_indices_v2i64_ext0(ptr %a) {
; CHECK-LABEL: @vector_splat_indices_v2i64_ext0(
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1 change: 1 addition & 0 deletions llvm/test/Transforms/InstSimplify/gep.ll
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@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -passes=instsimplify < %s | FileCheck %s
; RUN: opt -S -passes=instsimplify -use-constant-int-for-fixed-length-splat < %s | FileCheck %s

target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"

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