Handle constant int -> ptr casts of lvalue results.

 - PR3463 (again).

llvm-svn: 65133

2 files changed, 20 insertions, 8 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 0fcbdf12f06..64d3fdd8a73 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -54,6 +54,7 @@ struct EvalInfo {
 static bool EvaluateLValue(const Expr *E, APValue &Result, EvalInfo &Info);
 static bool EvaluatePointer(const Expr *E, APValue &Result, EvalInfo &Info);
 static bool EvaluateInteger(const Expr *E, APSInt  &Result, EvalInfo &Info);
+static bool EvaluateIntegerOrLValue(const Expr *E, APValue  &Result, EvalInfo &Info);
 static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
 static bool EvaluateComplex(const Expr *E, APValue &Result, EvalInfo &Info);
 
@@ -351,11 +352,17 @@ APValue PointerExprEvaluator::VisitCastExpr(const CastExpr* E) {
   }
   
   if (SubExpr->getType()->isIntegralType()) {
-    llvm::APSInt Result(32);
-    if (EvaluateInteger(SubExpr, Result, Info)) {
-      Result.extOrTrunc((unsigned)Info.Ctx.getTypeSize(E->getType()));
-      return APValue(0, Result.getZExtValue());
+    APValue Result;
+    if (!EvaluateIntegerOrLValue(SubExpr, Result, Info))
+      return APValue();
+
+    if (Result.isInt()) {
+      Result.getInt().extOrTrunc((unsigned)Info.Ctx.getTypeSize(E->getType()));
+      return APValue(0, Result.getInt().getZExtValue());
     }
+    
+    // Cast is of an lvalue, no need to change value.
+    return Result;
   }
 
   if (SubExpr->getType()->isFunctionType() ||
@@ -587,15 +594,17 @@ private:
 };
 } // end anonymous namespace
 
-static bool EvaluateInteger(const Expr* E, APSInt &Result, EvalInfo &Info) {
+static bool EvaluateIntegerOrLValue(const Expr* E, APValue &Result, EvalInfo &Info) {
   if (!E->getType()->isIntegralType())
     return false;
   
+  return IntExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E));
+}
+
+static bool EvaluateInteger(const Expr* E, APSInt &Result, EvalInfo &Info) {
   APValue Val;
-  if (!IntExprEvaluator(Info, Val).Visit(const_cast<Expr*>(E)) ||
-      !Val.isInt())
+  if (!EvaluateIntegerOrLValue(E, Val, Info) || !Val.isInt())
     return false;
-
   Result = Val.getInt();
   return true;
 }
diff --git a/clang/test/CodeGen/const-init.c b/clang/test/CodeGen/const-init.c
index 957e3733e41..128bbb54f33 100644
--- a/clang/test/CodeGen/const-init.c
+++ b/clang/test/CodeGen/const-init.c
@@ -76,4 +76,7 @@ int g15 = (int) (char) ((void*) 0 + 255);
 // RUN: grep '@g16 = global i64 4294967295' %t &&
 long long g16 = (long long) ((void*) 0xFFFFFFFF);
 
+// RUN: grep '@g17 = global i32\* @g15' %t &&
+int *g17 = (int *) ((long) &g15);
+
 // RUN: true