[cfe-commits] r110116 - /cfe/trunk/lib/Frontend/InitPreprocessor.cpp

[Chris Lattner]

Author: lattner
Date: Tue Aug  3 11:48:42 2010
New Revision: 110116

URL: http://llvm.org/viewvc/llvm-project?rev=110116&view=rev
Log:
fix some undefined behavior, PR7779.

Modified:
    cfe/trunk/lib/Frontend/InitPreprocessor.cpp

Modified: cfe/trunk/lib/Frontend/InitPreprocessor.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/InitPreprocessor.cpp?rev=110116&r1=110115&r2=110116&view=diff
==============================================================================
--- cfe/trunk/lib/Frontend/InitPreprocessor.cpp (original)
+++ cfe/trunk/lib/Frontend/InitPreprocessor.cpp Tue Aug  3 11:48:42 2010
@@ -169,9 +169,10 @@
                            llvm::StringRef ValSuffix, bool isSigned,
                            MacroBuilder& Builder) {
   long long MaxVal;
-  if (isSigned)
-    MaxVal = (1LL << (TypeWidth - 1)) - 1;
-  else
+  if (isSigned) {
+    assert(TypeWidth != 1);
+    MaxVal = ~0ULL >> (65-TypeWidth);
+  } else
     MaxVal = ~0LL >> (64-TypeWidth);
 
   Builder.defineMacro(MacroName, llvm::Twine(MaxVal) + ValSuffix);