Hi! > -----Original Message----- > From: Segher Boessenkool [mailto:seg...@kernel.crashing.org] > Sent: Monday, March 23, 2020 8:10 PM > To: Yangfei (Felix) <felix.y...@huawei.com> > Cc: gcc-patches@gcc.gnu.org; Zhanghaijian (A) <z.zhanghaij...@huawei.com> > Subject: Re: [PATCH PR94026] combine missed opportunity to simplify > comparisons with zero > > Yeah, maybe not in simplify-rtx.c, hrm. There is SELECT_CC_MODE for these > things, and combine knows about that (not many passes do).
I modified combine emitting a simple AND operation instead of making one zero_extract for this scenario. Attached please find the new patch. Hope this solves both of our concerns. gcc +2020-03-24 Felix Yang <felix.y...@huawei.com> + + PR rtl-optimization/94026 + * combine.c (make_compound_operation_int): If we are have (and + (lshiftrt X C) M) and M is a constant that would select a field + of bits within an item, but not the entire word, fold this into + a simple AND if we are in an equality comparison. gcc/testsuite +2020-03-24 Felix Yang <felix.y...@huawei.com> + + PR rtl-optimization/94026 + * gcc.dg/pr94026.c: New test. Thanks, Felix
pr94026-v1.patch
Description: pr94026-v1.patch
