On Tue, Mar 22, 2016 at 6:40 PM, Richard Henderson <r...@redhat.com> wrote: > In PR68142 you added a check for overflow + __INT_MIN__. > I can't figure out why the check for __INT_MIN__, except > that it seems specific to the test case you examined. > > And indeed, this test case shows how things go wrong > with other distributed folding leading to overflow.
Huh, not sure what I was thinking .. but I remember being on a hunt through various INT_MIN related overflow bugs when running into this one. > I added two tests, one signed, one unsigned. The second > verifies that we do still fold for the defined-overflow case. > > Ok? Ok. Note that always when I find bugs in extract_muldiv and try to decipher what it does I think we need to rip that out, replacing it with some simple patterns and leaving the rest to passes like reassoc. It's simply a beast that proved to be a can of worms... Thanks, Richard. > > r~
