On Tue, Aug 01, 2023 at 01:52:16PM +0530, Prathamesh Kulkarni wrote: > On Tue, 1 Aug 2023 at 05:20, Jeff Law <jeffreya...@gmail.com> wrote: > > > > > > > > On 7/31/23 15:43, Prathamesh Kulkarni via Gcc-patches wrote: > > > On Mon, 19 Jun 2023 at 19:59, Stefan Schulze Frielinghaus via > > > Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > >> > > >> Comparisons between memory and constants might be done in a smaller mode > > >> resulting in smaller constants which might finally end up as immediates > > >> instead of in the literal pool. > > >> > > >> For example, on s390x a non-symmetric comparison like > > >> x <= 0x3fffffffffffffff > > >> results in the constant being spilled to the literal pool and an 8 byte > > >> memory comparison is emitted. Ideally, an equivalent comparison > > >> x0 <= 0x3f > > >> where x0 is the most significant byte of x, is emitted where the > > >> constant is smaller and more likely to materialize as an immediate. > > >> > > >> Similarly, comparisons of the form > > >> x >= 0x4000000000000000 > > >> can be shortened into x0 >= 0x40. > > >> > > >> Bootstrapped and regtested on s390x, x64, aarch64, and powerpc64le. > > >> Note, the new tests show that for the mentioned little-endian targets > > >> the optimization does not materialize since either the costs of the new > > >> instructions are higher or they do not match. Still ok for mainline? > > > Hi Stefan, > > > Unfortunately this patch (committed in > > > 7cdd0860949c6c3232e6cff1d7ca37bb5234074c) > > > caused the following ICE on armv8l-unknown-linux-gnu: > > > during RTL pass: combine > > > ../../../gcc/libgcc/fixed-bit.c: In function ‘__gnu_saturate1sq’: > > > ../../../gcc/libgcc/fixed-bit.c:210:1: internal compiler error: in > > > decompose, at rtl.h:2297 > > > 210 | } > > > | ^ > > > 0xaa23e3 wi::int_traits<std::pair<rtx_def*, machine_mode> > > >> ::decompose(long long*, unsigned int, std::pair<rtx_def*, > > > machine_mode> const&) > > > ../../gcc/gcc/rtl.h:2297 > > [ ... ] > > Yea, we're seeing something very similar on nios2-linux-gnu building the > > kernel. > > > > Prathamesh, can you extract the .i file for fixed-bit on armv8 and open > > a bug for this issue, attaching the .i file as well as the right command > > line options necessary to reproduce the failure. THat way Stefan can > > tackle it with a cross compiler. > Hi Jeff, > Filed the issue in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110867
Hi Prathamesh, Sorry for the inconvenience. I will have a look at this and thanks for the small reproducer. I already started to come up with a cross compiler. Thanks, Stefan > > Thanks, > Prathamesh > > > > Thanks, > > jeff
