[LLVM][IR] When evaluating GEP offsets don't assume ConstantInt is a scalar. #117162
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@llvm/pr-subscribers-llvm-ir @llvm/pr-subscribers-llvm-analysis Author: Paul Walker (paulwalker-arm) ChangesFull diff: https://github.com/llvm/llvm-project/pull/117162.diff 4 Files Affected:
diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 1971c28fc4c4de..47b96e00c7765a 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -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);
diff --git a/llvm/lib/IR/Operator.cpp b/llvm/lib/IR/Operator.cpp
index 199eb4d90f5565..522e2ba9e59acf 100644
--- a/llvm/lib/IR/Operator.cpp
+++ b/llvm/lib/IR/Operator.cpp
@@ -127,8 +127,10 @@ bool GEPOperator::accumulateConstantOffset(
// Fast path for canonical getelementptr i8 form.
if (SourceType->isIntegerTy(8) && !ExternalAnalysis) {
if (auto *CI = dyn_cast<ConstantInt>(Index.front())) {
- Offset += CI->getValue().sextOrTrunc(Offset.getBitWidth());
- return true;
+ if (CI->getType()->isIntegerTy()) {
+ Offset += CI->getValue().sextOrTrunc(Offset.getBitWidth());
+ return true;
+ }
}
return false;
}
@@ -163,28 +165,30 @@ bool GEPOperator::accumulateConstantOffset(
Value *V = GTI.getOperand();
StructType *STy = GTI.getStructTypeOrNull();
// Handle ConstantInt if possible.
- if (auto ConstOffset = dyn_cast<ConstantInt>(V)) {
- if (ConstOffset->isZero())
- continue;
- // if the type is scalable and the constant is not zero (vscale * n * 0 =
- // 0) bailout.
- if (ScalableType)
- return false;
- // Handle a struct index, which adds its field offset to the pointer.
- if (STy) {
- unsigned ElementIdx = ConstOffset->getZExtValue();
- const StructLayout *SL = DL.getStructLayout(STy);
- // Element offset is in bytes.
- if (!AccumulateOffset(
- APInt(Offset.getBitWidth(), SL->getElementOffset(ElementIdx)),
- 1))
+ if (V->getType()->isIntegerTy()) {
+ if (auto ConstOffset = dyn_cast<ConstantInt>(V)) {
+ if (ConstOffset->isZero())
+ continue;
+ // if the type is scalable and the constant is not zero (vscale * n * 0
+ // = 0) bailout.
+ if (ScalableType)
+ return false;
+ // Handle a struct index, which adds its field offset to the pointer.
+ if (STy) {
+ unsigned ElementIdx = ConstOffset->getZExtValue();
+ const StructLayout *SL = DL.getStructLayout(STy);
+ // Element offset is in bytes.
+ if (!AccumulateOffset(
+ APInt(Offset.getBitWidth(), SL->getElementOffset(ElementIdx)),
+ 1))
+ return false;
+ continue;
+ }
+ if (!AccumulateOffset(ConstOffset->getValue(),
+ GTI.getSequentialElementStride(DL)))
return false;
continue;
}
- if (!AccumulateOffset(ConstOffset->getValue(),
- GTI.getSequentialElementStride(DL)))
- return false;
- continue;
}
// The operand is not constant, check if an external analysis was provided.
diff --git a/llvm/test/Transforms/InstCombine/gep-vector-indices.ll b/llvm/test/Transforms/InstCombine/gep-vector-indices.ll
index e9534e45ec141d..9f33f4e9c206a0 100644
--- a/llvm/test/Transforms/InstCombine/gep-vector-indices.ll
+++ b/llvm/test/Transforms/InstCombine/gep-vector-indices.ll
@@ -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(
diff --git a/llvm/test/Transforms/InstSimplify/gep.ll b/llvm/test/Transforms/InstSimplify/gep.ll
index b23494fc56aa4e..a330f5cbc92681 100644
--- a/llvm/test/Transforms/InstSimplify/gep.ll
+++ b/llvm/test/Transforms/InstSimplify/gep.ll
@@ -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"
|
nikic
reviewed
Nov 21, 2024
llvm/lib/IR/Operator.cpp
Outdated
| APInt(Offset.getBitWidth(), SL->getElementOffset(ElementIdx)), | ||
| 1)) | ||
| if (V->getType()->isIntegerTy()) { | ||
| if (auto ConstOffset = dyn_cast<ConstantInt>(V)) { |
There was a problem hiding this comment.
In the interest of keeping the indentation down, I'd write this as:
auto *ConstOffset = dyn_cast<ConstantInt>(V);
if (ConstOffset && ConstOffset->getType()->isIntegerTy()) {
}
llvm/lib/IR/Operator.cpp
Outdated
| continue; | ||
| } | ||
| if (!AccumulateOffset(ConstOffset->getValue(), | ||
| GTI.getSequentialElementStride(DL))) |
There was a problem hiding this comment.
Also update the very similar code in collectOffset() below?
There was a problem hiding this comment.
Done. I've been trying to rely purely on existing testing but it seems this was not covered so I've added a new one.
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nikic
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Nov 22, 2024
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/10688 Here is the relevant piece of the build log for the reference |
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