Revert "[ValueTracking] Improve isKnowNonZero for Ints"
This reverts commit 3b137a495686bd6018d115ea82fb8bb7718349fd.
As reported in https://reviews.llvm.org/D60846, this is causing
miscompiles.
llvm-svn: 360260
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 839f539..5457544 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1893,9 +1893,10 @@
return false;
}
-static bool isKnownNonZeroFromDominatingCondition(const Value *V,
+static bool isKnownNonNullFromDominatingCondition(const Value *V,
const Instruction *CtxI,
const DominatorTree *DT) {
+ assert(V->getType()->isPointerTy() && "V must be pointer type");
assert(!isa<ConstantData>(V) && "Did not expect ConstantPointerNull");
if (!CtxI || !DT)
@@ -1908,15 +1909,14 @@
break;
NumUsesExplored++;
- // If the value is a pointer and used as an argument to a call or invoke,
- // then argument attributes may provide an answer about null-ness.
- if (V->getType()->isPointerTy())
- if (auto CS = ImmutableCallSite(U))
- if (auto *CalledFunc = CS.getCalledFunction())
- for (const Argument &Arg : CalledFunc->args())
- if (CS.getArgOperand(Arg.getArgNo()) == V &&
- Arg.hasNonNullAttr() && DT->dominates(CS.getInstruction(), CtxI))
- return true;
+ // If the value is used as an argument to a call or invoke, then argument
+ // attributes may provide an answer about null-ness.
+ if (auto CS = ImmutableCallSite(U))
+ if (auto *CalledFunc = CS.getCalledFunction())
+ for (const Argument &Arg : CalledFunc->args())
+ if (CS.getArgOperand(Arg.getArgNo()) == V &&
+ Arg.hasNonNullAttr() && DT->dominates(CS.getInstruction(), CtxI))
+ return true;
// Consider only compare instructions uniquely controlling a branch
CmpInst::Predicate Pred;
@@ -2064,11 +2064,11 @@
}
- if (isKnownNonZeroFromDominatingCondition(V, Q.CxtI, Q.DT))
- return true;
-
// Check for recursive pointer simplifications.
if (V->getType()->isPointerTy()) {
+ if (isKnownNonNullFromDominatingCondition(V, Q.CxtI, Q.DT))
+ return true;
+
// Look through bitcast operations, GEPs, and int2ptr instructions as they
// do not alter the value, or at least not the nullness property of the
// value, e.g., int2ptr is allowed to zero/sign extend the value.