On 08/22/18 00:43, Jeff Law wrote: > [ I'm still digesting, but saw something in this that ought to be broken > out... ] > > On 08/19/2018 09:55 AM, Bernd Edlinger wrote: >> diff -Npur gcc/tree-ssa-dse.c gcc/tree-ssa-dse.c >> --- gcc/tree-ssa-dse.c 2018-07-18 21:21:34.000000000 +0200 >> +++ gcc/tree-ssa-dse.c 2018-08-19 14:29:32.344498771 +0200 >> @@ -248,6 +248,12 @@ compute_trims (ao_ref *ref, sbitmap live >> residual handling in mem* and str* functions is usually >> reasonably efficient. */ >> *trim_tail = last_orig - last_live; >> + /* Don't fold away an out of bounds access, as this defeats proper >> + warnings. */ >> + if (*trim_tail >> + && compare_tree_int (TYPE_SIZE_UNIT (TREE_TYPE (ref->base)), >> + last_orig) <= 0) >> + *trim_tail = 0; >> } >> else >> *trim_tail = 0; > This seems like a good change in and of itself and should be able to go > forward without further review work. Consider this hunk approved, > along with any testsuite you have which tickles this code (I didn't > immediately see one attached to this patch. But I could have missed it). >
Sorry, for not being clear on this. I needed both hunks "Don't fold away an out of bounds access, as this defeats proper warnings" to prevent a regression on gcc.dg/Wstringop-overflow-5.c, and surprise surprise, the xfail in gcc.dg/Wstringop-overflow-6.c suddenly popped up. So without the unsafe range info, gcc.dg/Wstringop-overflow-5.c needs both hunks to not regress, but gcc.dg/Wstringop-overflow-6.c only needs the other one I committed yesterday. So unfortunately I have no test case except gcc.dg/Wstringop-overflow-5.c for that. Still OK? Bernd.
