fix PR5436 by making the 'simple' case of SRoA not promote out of range
array indexes. The "complex" case of SRoA still handles them, and correctly.
This fixes a weirdness where we'd correctly avoid transforming A[0][42] if
the 42 was too large, but we'd only do it if it was one gep, not two separate
ones.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90007 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index 047d279..ae6ad74 100644
--- a/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -469,15 +469,41 @@
case Instruction::GetElementPtr: {
GetElementPtrInst *GEP = cast<GetElementPtrInst>(User);
bool AreAllZeroIndices = isFirstElt;
- if (GEP->getNumOperands() > 1) {
- if (!isa<ConstantInt>(GEP->getOperand(1)) ||
- !cast<ConstantInt>(GEP->getOperand(1))->isZero())
- // Using pointer arithmetic to navigate the array.
- return MarkUnsafe(Info);
-
- if (AreAllZeroIndices)
- AreAllZeroIndices = GEP->hasAllZeroIndices();
+ if (GEP->getNumOperands() > 1 &&
+ (!isa<ConstantInt>(GEP->getOperand(1)) ||
+ !cast<ConstantInt>(GEP->getOperand(1))->isZero()))
+ // Using pointer arithmetic to navigate the array.
+ return MarkUnsafe(Info);
+
+ // Verify that any array subscripts are in range.
+ for (gep_type_iterator GEPIt = gep_type_begin(GEP),
+ E = gep_type_end(GEP); GEPIt != E; ++GEPIt) {
+ // Ignore struct elements, no extra checking needed for these.
+ if (isa<StructType>(*GEPIt))
+ continue;
+
+ // This GEP indexes an array. Verify that this is an in-range
+ // constant integer. Specifically, consider A[0][i]. We cannot know that
+ // the user isn't doing invalid things like allowing i to index an
+ // out-of-range subscript that accesses A[1]. Because of this, we have
+ // to reject SROA of any accesses into structs where any of the
+ // components are variables.
+ ConstantInt *IdxVal = dyn_cast<ConstantInt>(GEPIt.getOperand());
+ if (!IdxVal) return MarkUnsafe(Info);
+
+ // Are all indices still zero?
+ AreAllZeroIndices &= IdxVal->isZero();
+
+ if (const ArrayType *AT = dyn_cast<ArrayType>(*GEPIt)) {
+ if (IdxVal->getZExtValue() >= AT->getNumElements())
+ return MarkUnsafe(Info);
+ } else if (const VectorType *VT = dyn_cast<VectorType>(*GEPIt)) {
+ if (IdxVal->getZExtValue() >= VT->getNumElements())
+ return MarkUnsafe(Info);
+ }
}
+
+
isSafeElementUse(GEP, AreAllZeroIndices, AI, Info);
if (Info.isUnsafe) return;
break;