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| author | Marek Polacek <polacek@redhat.com> | 2015-08-12 17:25:23 +0000 |
|---|---|---|
| committer | Marek Polacek <mpolacek@gcc.gnu.org> | 2015-08-12 17:25:23 +0000 |
| commit | b893e375096038ac99521a97b7fa346b016bdb78 (patch) | |
| tree | 61fb3ae13f36228936da84dc60d9e477d727f37e /gcc/c-family | |
| parent | bb2978b8fd41165054ffe3cfcfa5311fffaf13cd (diff) | |
| download | gcc-b893e375096038ac99521a97b7fa346b016bdb78.zip gcc-b893e375096038ac99521a97b7fa346b016bdb78.tar.gz gcc-b893e375096038ac99521a97b7fa346b016bdb78.tar.bz2 | |
re PR c++/55095 (Wshift-overflow)
PR c++/55095
* c-common.c (maybe_warn_shift_overflow): Properly handle
left-shifting 1 into the sign bit.
* c-c++-common/Wshift-overflow-6.c: New test.
* c-c++-common/Wshift-overflow-7.c: New test.
* g++.dg/cpp1y/left-shift-2.C: New test.
From-SVN: r226826
Diffstat (limited to 'gcc/c-family')
| -rw-r--r-- | gcc/c-family/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/c-family/c-common.c | 7 |
2 files changed, 9 insertions, 4 deletions
diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog index af1f098..c67c26c 100644 --- a/gcc/c-family/ChangeLog +++ b/gcc/c-family/ChangeLog @@ -1,3 +1,9 @@ +2015-08-12 Marek Polacek <polacek@redhat.com> + + PR c++/55095 + * c-common.c (maybe_warn_shift_overflow): Properly handle + left-shifting 1 into the sign bit. + 2015-08-09 Manuel López-Ibáñez <manu@gcc.gnu.org> * c.opt (Wchkp): Use LangEnabledBy instead of EnabledBy. diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c index f6c5ddd..13175d8 100644 --- a/gcc/c-family/c-common.c +++ b/gcc/c-family/c-common.c @@ -12442,9 +12442,10 @@ maybe_warn_shift_overflow (location_t loc, tree op0, tree op1) if (TYPE_UNSIGNED (type0)) return false; + unsigned int min_prec = (wi::min_precision (op0, SIGNED) + + TREE_INT_CST_LOW (op1)); /* Handle the left-shifting 1 into the sign bit case. */ - if (integer_onep (op0) - && compare_tree_int (op1, prec0 - 1) == 0) + if (min_prec == prec0 + 1) { /* Never warn for C++14 onwards. */ if (cxx_dialect >= cxx14) @@ -12456,8 +12457,6 @@ maybe_warn_shift_overflow (location_t loc, tree op0, tree op1) return true; } - unsigned int min_prec = (wi::min_precision (op0, SIGNED) - + TREE_INT_CST_LOW (op1)); bool overflowed = min_prec > prec0; if (overflowed && c_inhibit_evaluation_warnings == 0) warning_at (loc, OPT_Wshift_overflow_, |