https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65698
--- Comment #3 from Yuri Rumyantsev <ysrumyan at gmail dot com> ---
I see that this bug was no considered for a while.
Here is my additional comment.
First of all, this test was extracted from bzip2 benchmark, mainGTU function.
The problem is that (1) tree optimizer collects cse for i1 * 2 and i2 * 2;
(2) Forward propagation pass do not substitute it back to address computation
since use_killed_between is very simplified it handles only simple basic block
or semi-hammock:
/* Finally, if DEF_BB is the sole predecessor of TARGET_BB. */
if (single_pred_p (target_bb)
&& single_pred (target_bb) == def_bb)
This function must be enhanced to handle arbitrary cfg.
Note that this deficiency increases register pressure on 2 and we have more
spills/fills for x86 32-bit target.
