[PATCH PR100740]Fix overflow check in simplifying exit cond comparing two IVs.

[bin.cheng via Gcc-patches]

Hi,
As described in patch summary, this fixes the wrong code issue by adding 
overflow-ness
check for iv1.step - iv2.step.

Bootstrap and test on x86_64.  Any comments?

Thanks,
bin

pr100740-20210525.txt
Description: Binary data