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

1 files changed, 13 insertions, 13 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 839f539707a..54575441b71 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1893,9 +1893,10 @@ static bool isGEPKnownNonNull(const GEPOperator *GEP, unsigned Depth,
   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 @@ static bool isKnownNonZeroFromDominatingCondition(const Value *V,
       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 @@ bool isKnownNonZero(const Value *V, unsigned Depth, const Query &Q) {
   }
 
 
-  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.