Use is.constant intrinsic for __builtin_constant_p

Summary:
A __builtin_constant_p may end up with a constant after inlining. Use
the is.constant intrinsic if it's a variable that's in a context where
it may resolve to a constant, e.g., an argument to a function after
inlining.

Reviewers: rsmith, shafik

Subscribers: jfb, kristina, cfe-commits, nickdesaulniers, jyknight

Differential Revision: https://reviews.llvm.org/D54355

llvm-svn: 347294

1 files changed, 8 insertions, 4 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 980dbf9921f..eab07b166da 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -5795,6 +5795,8 @@ Sema::BuildCompoundLiteralExpr(SourceLocation LParenLoc, TypeSourceInfo *TInfo,
           ? VK_RValue
           : VK_LValue;
 
+  if (isFileScope)
+    LiteralExpr = ConstantExpr::Create(Context, LiteralExpr);
   Expr *E = new (Context) CompoundLiteralExpr(LParenLoc, TInfo, literalType,
                                               VK, LiteralExpr, isFileScope);
   if (isFileScope) {
@@ -5803,7 +5805,6 @@ Sema::BuildCompoundLiteralExpr(SourceLocation LParenLoc, TypeSourceInfo *TInfo,
         !literalType->isDependentType()) // C99 6.5.2.5p3
       if (CheckForConstantInitializer(LiteralExpr, literalType))
         return ExprError();
-    E = new (Context) ConstantExpr(E);
   } else if (literalType.getAddressSpace() != LangAS::opencl_private &&
              literalType.getAddressSpace() != LangAS::Default) {
     // Embedded-C extensions to C99 6.5.2.5:
@@ -14167,12 +14168,15 @@ Sema::VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
     return ExprError();
   }
 
+  if (!isa<ConstantExpr>(E))
+    E = ConstantExpr::Create(Context, E);
+
   // Circumvent ICE checking in C++11 to avoid evaluating the expression twice
   // in the non-ICE case.
   if (!getLangOpts().CPlusPlus11 && E->isIntegerConstantExpr(Context)) {
     if (Result)
       *Result = E->EvaluateKnownConstIntCheckOverflow(Context);
-    return new (Context) ConstantExpr(E);
+    return E;
   }
 
   Expr::EvalResult EvalResult;
@@ -14190,7 +14194,7 @@ Sema::VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
   if (Folded && getLangOpts().CPlusPlus11 && Notes.empty()) {
     if (Result)
       *Result = EvalResult.Val.getInt();
-    return new (Context) ConstantExpr(E);
+    return E;
   }
 
   // If our only note is the usual "invalid subexpression" note, just point
@@ -14218,7 +14222,7 @@ Sema::VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
 
   if (Result)
     *Result = EvalResult.Val.getInt();
-  return new (Context) ConstantExpr(E);
+  return E;
 }
 
 namespace {