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| author | Joseph Myers <joseph@codesourcery.com> | 2013-12-10 01:23:37 +0000 |
|---|---|---|
| committer | Joseph Myers <jsm28@gcc.gnu.org> | 2013-12-10 01:23:37 +0000 |
| commit | 3a4efce7c246b190ef35a8ce1f108f572274521f (patch) | |
| tree | 17fee4f3cb77d383b7ed61dc4891d6ab12174ac5 /libcpp | |
| parent | e73d2479dd03132a1147c013426ea8e88c10d2ff (diff) | |
| download | gcc-3a4efce7c246b190ef35a8ce1f108f572274521f.zip gcc-3a4efce7c246b190ef35a8ce1f108f572274521f.tar.gz gcc-3a4efce7c246b190ef35a8ce1f108f572274521f.tar.bz2 | |
re PR preprocessor/55715 (bogus overflow warning for #if A-B when A<0 & B==minimum integer)
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.
From-SVN: r205846
Diffstat (limited to 'libcpp')
| -rw-r--r-- | libcpp/ChangeLog | 6 | ||||
| -rw-r--r-- | libcpp/expr.c | 17 |
2 files changed, 22 insertions, 1 deletions
diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog index c3391b4..4a06d0c 100644 --- a/libcpp/ChangeLog +++ b/libcpp/ChangeLog @@ -1,3 +1,9 @@ +2013-12-09 Joseph Myers <joseph@codesourcery.com> + + PR preprocessor/55715 + * expr.c (num_binary_op): Implement subtraction directly rather + than with negation and falling through into addition case. + 2013-11-18 Bill Schmidt <wschmidt@linux.vnet.ibm.com> * lex.c (search_line_fast): Correct for little endian. diff --git a/libcpp/expr.c b/libcpp/expr.c index c009807..1e17b00 100644 --- a/libcpp/expr.c +++ b/libcpp/expr.c @@ -1836,7 +1836,22 @@ num_binary_op (cpp_reader *pfile, cpp_num lhs, cpp_num rhs, enum cpp_ttype op) /* Arithmetic. */ case CPP_MINUS: - rhs = num_negate (rhs, precision); + result.low = lhs.low - rhs.low; + result.high = lhs.high - rhs.high; + if (result.low > lhs.low) + result.high--; + result.unsignedp = lhs.unsignedp || rhs.unsignedp; + result.overflow = false; + + result = num_trim (result, precision); + if (!result.unsignedp) + { + bool lhsp = num_positive (lhs, precision); + result.overflow = (lhsp != num_positive (rhs, precision) + && lhsp != num_positive (result, precision)); + } + return result; + case CPP_PLUS: result.low = lhs.low + rhs.low; result.high = lhs.high + rhs.high; |