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Catch overflow of negate. This allows us to emit: 

t.c:2:17: warning: integer overflow in preprocessor expression
#if -(INTMAX_MAX+1)
                ^
t.c:2:5: warning: integer overflow in preprocessor expression
#if -(INTMAX_MAX+1)
    ^

GCC has some seriously confused source locations in this case:
t.c:2:19: warning: integer overflow in preprocessor expression
t.c:2:20: warning: integer overflow in preprocessor expression

column 19/20 are off the end of the line.

llvm-svn: 39404
This commit is contained in:
Chris Lattner 2007-04-11 03:42:36 +00:00
parent 028c7decef
commit 7e61ac5a3c
1 changed files with 14 additions and 1 deletions
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15
clang/Lex/PPExpressions.cpp
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@ -261,13 +261,26 @@ static bool EvaluateValue(APSInt &Result, LexerToken &PeekTok,
// Unary plus doesn't modify the value.
PP.LexNonComment(PeekTok);
return EvaluateValue(Result, PeekTok, DT, ValueLive, PP);
case tok::minus:
case tok::minus: {
SourceLocation Loc = PeekTok.getLocation();
PP.LexNonComment(PeekTok);
if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
// C99 6.5.3.3p3: The sign of the result matches the sign of the operand.
Result = -Result;
bool Overflow = false;
if (Result.isUnsigned())
Overflow = !Result.isPositive();
else if (Result.isMinSignedValue())
Overflow = true; // -MININT is the only thing that overflows.
// If this operator is live and overflowed, report the issue.
if (Overflow && ValueLive)
PP.Diag(Loc, diag::warn_pp_expr_overflow);
DT.State = DefinedTracker::Unknown;
return false;
}
case tok::tilde:
PP.LexNonComment(PeekTok);