[ValueTracking] Handle constant exprs in isKnownNonZero()

Handle constant expressions by falling through to the general
operator-based code. In particular, this adds support for bitcast
and GEP expressions.

1 files changed, 7 insertions, 13 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 81f606f..95f6e5d 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -2481,16 +2481,6 @@ bool isKnownNonZero(const Value *V, const APInt &DemandedElts, unsigned Depth,
       // Must be non-zero due to null test above.
       return true;
 
-    if (auto *CE = dyn_cast<ConstantExpr>(C)) {
-      // See the comment for IntToPtr/PtrToInt instructions below.
-      if (CE->getOpcode() == Instruction::IntToPtr ||
-          CE->getOpcode() == Instruction::PtrToInt)
-        if (Q.DL.getTypeSizeInBits(CE->getOperand(0)->getType())
-                .getFixedSize() <=
-            Q.DL.getTypeSizeInBits(CE->getType()).getFixedSize())
-          return isKnownNonZero(CE->getOperand(0), Depth, Q);
-    }
-
     // For constant vectors, check that all elements are undefined or known
     // non-zero to determine that the whole vector is known non-zero.
     if (auto *VecTy = dyn_cast<FixedVectorType>(C->getType())) {
@@ -2513,7 +2503,10 @@ bool isKnownNonZero(const Value *V, const APInt &DemandedElts, unsigned Depth,
       if (!GV->isAbsoluteSymbolRef() && !GV->hasExternalWeakLinkage() &&
           GV->getType()->getAddressSpace() == 0)
         return true;
-    } else
+    }
+
+    // For constant expressions, fall through to the Operator code below.
+    if (!isa<ConstantExpr>(V))
       return false;
   }
 
@@ -2529,7 +2522,7 @@ bool isKnownNonZero(const Value *V, const APInt &DemandedElts, unsigned Depth,
     }
   }
 
-  if (isKnownNonZeroFromAssume(V, Q))
+  if (!isa<Constant>(V) && isKnownNonZeroFromAssume(V, Q))
     return true;
 
   // Some of the tests below are recursive, so bail out if we hit the limit.
@@ -2565,7 +2558,8 @@ bool isKnownNonZero(const Value *V, const APInt &DemandedElts, unsigned Depth,
     }
   }
 
-  if (isKnownNonNullFromDominatingCondition(V, Q.CxtI, Q.DT))
+  if (!isa<Constant>(V) &&
+      isKnownNonNullFromDominatingCondition(V, Q.CxtI, Q.DT))
     return true;
 
   const Operator *I = dyn_cast<Operator>(V);