[Bug middle-end/56281] missed VRP optimization on i for signed i << n from undefined left shift in ISO C

2023-09-28 Thread vincent-gcc at vinc17 dot net via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56281 --- Comment #6 from Vincent Lefèvre --- (In reply to Jakub Jelinek from comment #1) > Given the amount of code in the wild that assumes 1 << 31 etc. work, I think > it would be a bad idea to try to optimize this for C99, especially when it > is

[Bug middle-end/56281] missed VRP optimization on i for signed i << n from undefined left shift in ISO C

2022-03-23 Thread vincent-gcc at vinc17 dot net via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56281 --- Comment #5 from Vincent Lefèvre --- I've clarified the bug title to say that this is a range on the first operand.