Use values cached in ConstantExprs for expression evaluation where

present. No functionality change intended. Differential Revision: https://reviews.llvm.org/D76438
llvm · Mar 21, 2020 · be10b7e · be10b7e
1 parent fc7233d
commit be10b7e
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Showing 4 changed files with 18 additions and 5 deletions.
diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
@@ -1056,6 +1056,9 @@ class ConstantExpr final
   bool isImmediateInvocation() const {
     return ConstantExprBits.IsImmediateInvocation;
   }
+  bool hasAPValueResult() const {
+    return ConstantExprBits.APValueKind != APValue::None;
+  }
   APValue getAPValueResult() const;
   APValue &getResultAsAPValue() const { return APValueResult(); }
   llvm::APSInt getResultAsAPSInt() const;

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
@@ -357,6 +357,8 @@ llvm::APSInt ConstantExpr::getResultAsAPSInt() const {
 }
 
 APValue ConstantExpr::getAPValueResult() const {
+  assert(hasAPValueResult());
+
   switch (ConstantExprBits.ResultKind) {
   case ConstantExpr::RSK_APValue:
     return APValueResult();
@@ -2722,9 +2724,6 @@ static Expr *IgnoreParensSingleStep(Expr *E) {
       return CE->getChosenSubExpr();
   }
 
-  else if (auto *CE = dyn_cast<ConstantExpr>(E))
-    return CE->getSubExpr();
-
   return E;
 }
 

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
@@ -6776,8 +6776,13 @@ class ExprEvaluatorBase
     return Error(E);
   }
 
-  bool VisitConstantExpr(const ConstantExpr *E)
-    { return StmtVisitorTy::Visit(E->getSubExpr()); }
+  bool VisitConstantExpr(const ConstantExpr *E) {
+    if (E->hasAPValueResult())
+      return DerivedSuccess(E->getAPValueResult(), E);
+
+    return StmtVisitorTy::Visit(E->getSubExpr());
+  }
+
   bool VisitParenExpr(const ParenExpr *E)
     { return StmtVisitorTy::Visit(E->getSubExpr()); }
   bool VisitUnaryExtension(const UnaryOperator *E)

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
@@ -15166,6 +15166,12 @@ Sema::VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
     return ExprError();
   }
 
+  ExprResult RValueExpr = DefaultLvalueConversion(E);
+  if (RValueExpr.isInvalid())
+    return ExprError();
+
+  E = RValueExpr.get();
+
   // Circumvent ICE checking in C++11 to avoid evaluating the expression twice
   // in the non-ICE case.
   if (!getLangOpts().CPlusPlus11 && E->isIntegerConstantExpr(Context)) {