https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114978
--- Comment #16 from chenglulu <chenglulu at loongson dot cn> ---
The performance degradation on LoongArch is caused by one commit：
commit e0e9499aeffdaca88f0f29334384aa5f710a81a4 (HEAD -> trunk)
Author: Richard Biener <rguent...@suse.de>
Date: Tue Mar 19 12:24:08 2024 +0100
tree-optimization/114151 - revert PR114074 fix
The following reverts the chrec_fold_multiply fix and only keeps
handling of constant overflow which keeps the original testcase
fixed. A better solution might involve ranger improvements or
tracking of assumptions during SCEV analysis similar to what niter
analysis does.
PR tree-optimization/114151
PR tree-optimization/114269
PR tree-optimization/114322
PR tree-optimization/114074
* tree-chrec.cc (chrec_fold_multiply): Restrict the use of
unsigned arithmetic when actual overflow on constant operands
is observed.
* gcc.dg/pr68317.c: Revert last change.
The scores before and after this patch are:
（-g -Ofast -march=la464）
r14-9539: 12.3
r14-9540: 9.26
