commit 028c7decef750f2449263c55a184e248db724f64
author Chris Lattner <sabre@nondot.org> Wed Apr 11 03:34:29 2007 +0000
committer Chris Lattner <sabre@nondot.org> Wed Apr 11 03:34:29 2007 +0000
tree bbf5d7e4b8c2b6bdcf1090df03dc6310d4fb6627
parent 9cc755d535460c94643e6be0b1edca215043006b

Overflow detection for +/-

llvm-svn: 39403

clang/Lex/PPExpressions.cpp

diff --git a/clang/Lex/PPExpressions.cpp b/clang/Lex/PPExpressions.cpp
index ecd7a54..4c17dd1 100644
--- a/clang/Lex/PPExpressions.cpp
+++ b/clang/Lex/PPExpressions.cpp
@@ -467,9 +467,19 @@
     }
     case tok::plus:
       Res = LHS + RHS;
+      if (LHS.isUnsigned())
+        Overflow = Res.ult(LHS);
+      else if (LHS.isPositive() == RHS.isPositive() &&
+               Res.isPositive() != LHS.isPositive())
+        Overflow = true;  // Overflow for signed addition.
       break;
     case tok::minus:
       Res = LHS - RHS;
+      if (LHS.isUnsigned())
+        Overflow = Res.ugt(LHS);
+      else if (LHS.isPositive() != RHS.isPositive() &&
+               Res.isPositive() != LHS.isPositive())
+        Overflow = true;  // Overflow for signed subtraction.
       break;
     case tok::lessequal:
       Res = LHS <= RHS;