[cfe-commits] r77344 - in /cfe/trunk: lib/AST/Expr.cpp test/Sema/unused-expr.c

[Chris Lattner]

Author: lattner
Date: Tue Jul 28 13:25:28 2009
New Revision: 77344

URL: http://llvm.org/viewvc/llvm-project?rev=77344&view=rev
Log:
fix PR4633: cast to void should silence the 'unused expression' warning.

Modified:
    cfe/trunk/lib/AST/Expr.cpp
    cfe/trunk/test/Sema/unused-expr.c

Modified: cfe/trunk/lib/AST/Expr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Expr.cpp?rev=77344&r1=77343&r2=77344&view=diff

==============================================================================
--- cfe/trunk/lib/AST/Expr.cpp (original)
+++ cfe/trunk/lib/AST/Expr.cpp Tue Jul 28 13:25:28 2009
@@ -593,11 +593,10 @@
     return true;
   }
   case CStyleCastExprClass:
-    // If this is a cast to void, check the operand.  Otherwise, the result of
-    // the cast is unused.
+    // If this is an explicit cast to void, allow it.  People do this when they
+    // think they know what they're doing :).
     if (getType()->isVoidType())
-      return cast<CastExpr>(this)->getSubExpr()
-               ->isUnusedResultAWarning(Loc, R1, R2);
+      return false;
     Loc = cast<CStyleCastExpr>(this)->getLParenLoc();
     R1 = cast<CStyleCastExpr>(this)->getSubExpr()->getSourceRange();
     return true;

Modified: cfe/trunk/test/Sema/unused-expr.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/unused-expr.c?rev=77344&r1=77343&r2=77344&view=diff

==============================================================================
--- cfe/trunk/test/Sema/unused-expr.c (original)
+++ cfe/trunk/test/Sema/unused-expr.c Tue Jul 28 13:25:28 2009
@@ -43,4 +43,11 @@
 {
   unsigned char c = 1;
   *a |= c, *b += c;
+
+
+  // PR4633
+  int y, x;
+  ((void)0), y = x;
 }
+
+