The reason is removing MINUS from safe_for_live_propagation. We did not do it on purpose, will roll back on V3.
> On 29 Nov 2023, at 19:46, Xi Ruoyao <xry...@xry111.site> wrote: > > On Wed, 2023-11-29 at 20:37 +0800, Xi Ruoyao wrote: >>> On Wed, 2023-11-29 at 17:33 +0800, Xi Ruoyao wrote: >>> On Mon, 2023-11-27 at 23:06 -0700, Jeff Law wrote: >>>> This has (of course) been tested on rv64. It's also been bootstrapped >>>> and regression tested on x86. Bootstrap and regression tested (C only) >>>> for m68k, sh4, sh4eb, alpha. Earlier versions were also bootstrapped >>>> and regression tested on ppc, hppa and s390x (C only for those as well). >>>> It's also been tested on the various crosses in my tester. So we've >>>> got reasonable coverage of 16, 32 and 64 bit targets, big and little >>>> endian, with and without SHIFT_COUNT_TRUNCATED and all kinds of other >>>> oddities. >>>> >>>> The included tests are for RISC-V only because not all targets are going >>>> to have extraneous extensions. There's tests from coremark, x264 and >>>> GCC's bz database. It probably wouldn't be hard to add aarch64 >>>> testscases. The BZs listed are improved by this patch for aarch64. >>> >>> I've successfully bootstrapped this on loongarch64-linux-gnu and tried >>> the added test cases. For loongarch64 the redundant extensions are >>> removed for core_bench_list.c, core_init_matrix.c, core_list_init.c, >>> matrix_add_const.c, and pr111384.c, but not mem-extend.c. > >> Follow up: no regression in GCC test suite on LoongArch. >> >>> Should I change something in LoongArch backend in order to make ext_dce >>> work for mem-extend.c too? If yes then any pointers? > > Hmm... This test seems not working even for RISC-V: > > $ ./gcc/cc1 -O2 ../gcc/gcc/testsuite/gcc.target/riscv/mem-extend.c -nostdinc > -fdump-rtl-ext_dce -march=rv64gc_zbb -mabi=lp64d -o- 2>&1 | grep -F zext.h > zext.h a5,a5 > zext.h a4,a4 > > and the 294r.ext_dce file does not contain "Successfully transformed > to:" lines. > > -- > Xi Ruoyao <xry...@xry111.site> > School of Aerospace Science and Technology, Xidian University
