Refactor some methods to look through bitcasts and GEPs on pointers into
a common collection of methods on Value, and share their implementation.
We had two variations in two different places already, and I need the
third variation for inline cost estimation.
Reviewed by Duncan Sands on IRC, but further comments here welcome.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152490 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index 370ab96..c024e92 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -1522,28 +1522,6 @@
return 0;
}
-/// stripPointerAdjustments - This is like Value::stripPointerCasts, but also
-/// removes inbounds gep operations, regardless of their indices.
-static Value *stripPointerAdjustmentsImpl(Value *V,
- SmallPtrSet<GEPOperator*, 8> &VisitedGEPs) {
- GEPOperator *GEP = dyn_cast<GEPOperator>(V);
- if (GEP == 0 || !GEP->isInBounds())
- return V;
-
- // If we've already seen this GEP, we will end up infinitely looping. This
- // can happen in unreachable code.
- if (!VisitedGEPs.insert(GEP))
- return V;
-
- return stripPointerAdjustmentsImpl(GEP->getOperand(0)->stripPointerCasts(),
- VisitedGEPs);
-}
-
-static Value *stripPointerAdjustments(Value *V) {
- SmallPtrSet<GEPOperator*, 8> VisitedGEPs;
- return stripPointerAdjustmentsImpl(V, VisitedGEPs);
-}
-
/// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
/// fold the result. If not, this returns null.
@@ -1625,9 +1603,9 @@
// Be more aggressive about stripping pointer adjustments when checking a
// comparison of an alloca address to another object. We can rip off all
// inbounds GEP operations, even if they are variable.
- LHSPtr = stripPointerAdjustments(LHSPtr);
+ LHSPtr = LHSPtr->stripInBoundsOffsets();
if (llvm::isIdentifiedObject(LHSPtr)) {
- RHSPtr = stripPointerAdjustments(RHSPtr);
+ RHSPtr = RHSPtr->stripInBoundsOffsets();
if (llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr)) {
// If both sides are different identified objects, they aren't equal
// unless they're null.
@@ -1644,7 +1622,7 @@
if (llvm::isKnownNonNull(LHSPtr) && isa<ConstantPointerNull>(RHSPtr))
return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
} else if (isa<Argument>(LHSPtr)) {
- RHSPtr = stripPointerAdjustments(RHSPtr);
+ RHSPtr = RHSPtr->stripInBoundsOffsets();
// An alloca can't be equal to an argument.
if (isa<AllocaInst>(RHSPtr))
return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));