As reported by pr68137 and pr68326, r230150 caused new issues.
Those ICEs are caused by adjust_range_with_scev getting range with overflowed constants min or max. So given there are too many places to generate OVF, we do a check in adjust_range_with_scev, to drop OVF flag when it's uncessary. This should fix the OVF side-effect caused by r230150. A simple regression testcase is included in this patch. bootstrap OK on x86-64 and aarch64, regression ok on both. For more background, please see discussion at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68317 OK for trunk? 2015-11-23 Richard Biener <rgue...@gcc.gnu.com> Jiong Wang <jiong.w...@arm.com> gcc/ PR tree-optimization/68137 PR tree-optimization/68326 * tree-vrp.c (adjust_range_with_scev): Call drop_tree_overflow if the final min and max are not infinity. gcc/testsuite/ * gcc.dg/pr68139.c: New testcase. -- Regards, Jiong
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index e2393e4..8efeb76 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -4331,6 +4331,17 @@ adjust_range_with_scev (value_range *vr, struct loop *loop, && is_positive_overflow_infinity (max))) return; + /* Even for valid range info, sometimes overflow flag will leak in. + As GIMPLE IL should have no constants with TREE_OVERFLOW set, we + drop them except for +-overflow_infinity which still need special + handling in vrp pass. */ + if (TREE_OVERFLOW_P (min) + && ! is_negative_overflow_infinity (min)) + min = drop_tree_overflow (min); + if (TREE_OVERFLOW_P (max) + && ! is_positive_overflow_infinity (max)) + max = drop_tree_overflow (max); + set_value_range (vr, VR_RANGE, min, max, vr->equiv); } diff --git a/gcc/testsuite/gcc.dg/pr68137.c b/gcc/testsuite/gcc.dg/pr68137.c new file mode 100644 index 0000000..a30e1ac --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr68137.c @@ -0,0 +1,14 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +void bar (int); + +void +foo () +{ + int index = 0; + for (index; index <= 10; index--) + /* Result of the following multiply will overflow + when converted to signed int. */ + bar((0xcafe + index) * 0xdead); +}