[Bug preprocessor/55715] bogus overflow warning for #if A-B when A<0 & B==minimum integer

[jsm28 at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55715

--- Comment #1 from Joseph S. Myers <jsm28 at gcc dot gnu.org> ---
Author: jsm28
Date: Tue Dec 10 01:23:37 2013
New Revision: 205846

URL: http://gcc.gnu.org/viewcvs?rev=205846&root=gcc&view=rev
Log:
    PR preprocessor/55715
libcpp:
    * expr.c (num_binary_op): Implement subtraction directly rather
    than with negation and falling through into addition case.

gcc/testsuite:
    * gcc.dg/cpp/expr-overflow-1.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/cpp/expr-overflow-1.c
Modified:
    trunk/gcc/testsuite/ChangeLog
    trunk/libcpp/ChangeLog
    trunk/libcpp/expr.c