[Clang][CodeGen] Use EvaluateAsBooleanCondition

Author: dtcxzyw

clang/lib/CodeGen/CGExpr.cpp

@@ -4823,11 +4823,12 @@ bool CodeGenFunction::isUnderlyingBasePointerConstantNull(const Expr *E) {
   // Workaround for old glibc's __PTR_ALIGN macro
   // If the condition can be constant evaluated, we check the selected arm.
   if (auto *Select = dyn_cast<ConditionalOperator>(UnderlyingBaseExpr)) {
-    if (auto *C = dyn_cast_if_present<llvm::Constant>(
-            ConstantEmitter(*this).tryEmitAbstract(
-                Select->getCond(), Select->getCond()->getType())))
+    bool EvalResult;
+    if (Select->getCond()->EvaluateAsBooleanCondition(EvalResult,
+                                                      getContext())) {
       return isUnderlyingBasePointerConstantNull(
-          C->isNullValue() ? Select->getFalseExpr() : Select->getTrueExpr());
+          EvalResult ? Select->getTrueExpr() : Select->getFalseExpr());
+    }
   }
   return getContext().isSentinelNullExpr(UnderlyingBaseExpr);
 }