[ValueTracking] Allow context-sensitive nullness check for non-pointers

Same as D60846 but with a fix for the problem encountered there which
was a missing context adjustment in the handling of PHI nodes.

The test that caused D60846 to be reverted was added in e15ab8f277c7.

Reviewers: nikic, nlopes, mkazantsev,spatel, dlrobertson, uabelho, hakzsam

Subscribers: hiraditya, bollu, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69571

1 files changed, 4 insertions, 5 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index bbf38999183..cc5acf5d010 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1902,8 +1902,8 @@ static bool isGEPKnownNonNull(const GEPOperator *GEP, unsigned Depth,
 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 (isa<Constant>(V))
+    return false;
 
   if (!CtxI || !DT)
     return false;
@@ -2078,12 +2078,11 @@ bool isKnownNonZero(const Value *V, unsigned Depth, const Query &Q) {
     }
   }
 
+  if (isKnownNonNullFromDominatingCondition(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.