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| author | Richard Biener <rguenther@suse.de> | 2017-06-14 11:40:20 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2017-06-14 11:40:20 +0000 |
| commit | 909263f855ae056b49b8fbbbcf594d7e9b90b434 (patch) | |
| tree | 438e6ca62418d179e447ddb69fbd318488a45f11 /gcc | |
| parent | c74985e3ee7f30091582908b1bdf3cdec5218897 (diff) | |
| download | gcc-909263f855ae056b49b8fbbbcf594d7e9b90b434.zip gcc-909263f855ae056b49b8fbbbcf594d7e9b90b434.tar.gz gcc-909263f855ae056b49b8fbbbcf594d7e9b90b434.tar.bz2 | |
re PR middle-end/81088 (UBSAN: false positive as a result of reassosiation)
2017-06-14 Richard Biener <rguenther@suse.de>
PR middle-end/81088
* fold-const.c (split_tree): Drop TREE_OVERFLOW flag from
literal constants.
(fold_binary_loc): When associating do not treat pre-existing
TREE_OVERFLOW on literal constants as a reason to allow
TREE_OVERFLOW on associated literal constants.
* c-c++-common/ubsan/pr81088.c: New testcase.
From-SVN: r249192
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 9 | ||||
| -rw-r--r-- | gcc/fold-const.c | 17 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/c-c++-common/ubsan/pr81088.c | 11 |
4 files changed, 34 insertions, 8 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 11e3533..09a1b98 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,12 @@ +2017-06-14 Richard Biener <rguenther@suse.de> + + PR middle-end/81088 + * fold-const.c (split_tree): Drop TREE_OVERFLOW flag from + literal constants. + (fold_binary_loc): When associating do not treat pre-existing + TREE_OVERFLOW on literal constants as a reason to allow + TREE_OVERFLOW on associated literal constants. + 2017-06-14 Eric Botcazou <ebotcazou@adacore.com> * config/sparc/sparc.h (MASK_ISA): Add MASK_LEON and MASK_LEON3. diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 74bbdb0..8559b1d 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -880,6 +880,13 @@ split_tree (location_t loc, tree in, tree type, enum tree_code code, } } + if (*litp + && TREE_OVERFLOW_P (*litp)) + *litp = drop_tree_overflow (*litp); + if (*minus_litp + && TREE_OVERFLOW_P (*minus_litp)) + *minus_litp = drop_tree_overflow (*minus_litp); + return var; } @@ -9703,11 +9710,6 @@ fold_binary_loc (location_t loc, + (lit0 != 0) + (lit1 != 0) + (minus_lit0 != 0) + (minus_lit1 != 0)))) { - bool any_overflows = false; - if (lit0) any_overflows |= TREE_OVERFLOW (lit0); - if (lit1) any_overflows |= TREE_OVERFLOW (lit1); - if (minus_lit0) any_overflows |= TREE_OVERFLOW (minus_lit0); - if (minus_lit1) any_overflows |= TREE_OVERFLOW (minus_lit1); var0 = associate_trees (loc, var0, var1, code, atype); con0 = associate_trees (loc, con0, con1, code, atype); lit0 = associate_trees (loc, lit0, lit1, code, atype); @@ -9738,9 +9740,8 @@ fold_binary_loc (location_t loc, } /* Don't introduce overflows through reassociation. */ - if (!any_overflows - && ((lit0 && TREE_OVERFLOW_P (lit0)) - || (minus_lit0 && TREE_OVERFLOW_P (minus_lit0)))) + if ((lit0 && TREE_OVERFLOW_P (lit0)) + || (minus_lit0 && TREE_OVERFLOW_P (minus_lit0))) return NULL_TREE; if (minus_lit0) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index d6fdd84..bd241de 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2017-06-14 Richard Biener <rguenther@suse.de> + + PR middle-end/81088 + * c-c++-common/ubsan/pr81088.c: New testcase. + 2017-06-14 Eric Botcazou <ebotcazou@adacore.com> * gcc.target/sparc/overflow-4.c: Add -mno-vis3. diff --git a/gcc/testsuite/c-c++-common/ubsan/pr81088.c b/gcc/testsuite/c-c++-common/ubsan/pr81088.c new file mode 100644 index 0000000..6753d77 --- /dev/null +++ b/gcc/testsuite/c-c++-common/ubsan/pr81088.c @@ -0,0 +1,11 @@ +/* { dg-do run } */ +/* { dg-options "-fsanitize=undefined -fsanitize-undefined-trap-on-error" } */ + +short s = 2; +short y = 1; +int i; +int main() +{ + i = -(s + (int)(~(unsigned)(0 / y))) + 0x7fffffff; + return 0; +} |