[ValueTracking] Instruction::isBinaryOp should be used for constexprs

[aqjune]

Summary

This is a simple patch that makes canCreateUndefOrPoison use
Instruction::isBinaryOp because BinaryOperator inherits Instruction.

[nikic]

LGTM

llvm/lib/Analysis/ValueTracking.cpp

static bool canCreateUndefOrPoison(const Operator *Op, bool PoisonOnly) {
   case Instruction::GetElementPtr: {
     const auto *GEP = cast<GEPOperator>(Op);
     return GEP->isInBounds();
   }
   default: {
     const auto *CE = dyn_cast<ConstantExpr>(Op);
     if (isa<CastInst>(Op) || (CE && CE->isCast()))
       return false;
-    else if (isa<BinaryOperator>(Op))
+    else if (Instruction::isBinaryOp(Opcode))
       return false;
     // Be conservative and return true.
     return true;
   }
   }
 }
 
 bool llvm::canCreateUndefOrPoison(const Operator *Op) {

llvm/test/Transforms/InstSimplify/freeze.ll

 ; CHECK-NEXT:    ret i32* getelementptr (i32, i32* @glb, i64 3)
 ;
   %r = freeze i32* getelementptr (i32, i32* @glb, i64 3)
   ret i32* %r
 }
 
 define i64 @ptrdiff() {
 ; CHECK-LABEL: @ptrdiff(
-; CHECK-NEXT:    [[R:%.*]] = freeze i64 sub (i64 ptrtoint (i16* @g to i64), i64 ptrtoint (i16* @g2 to i64))
-; CHECK-NEXT:    ret i64 [[R]]
+; CHECK-NEXT:    ret i64 sub (i64 ptrtoint (i16* @g to i64), i64 ptrtoint (i16* @g2 to i64))
 ;
   %i = ptrtoint i16* @g to i64
   %i2 = ptrtoint i16* @g2 to i64
   %diff = sub i64 %i, %i2
   %r = freeze i64 %diff
   ret i64 %r
 }