[Bug target/112431] RISC-V GCC-15 feature: Support register overlap on widen RVV instructions

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112431

--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Lehua Ding <lhtin@gcc.gnu.org>:

https://gcc.gnu.org/g:4418d55bcd1b7e0ef823981b6a781d7de5c38cce

commit r14-6054-g4418d55bcd1b7e0ef823981b6a781d7de5c38cce
Author: Juzhe-Zhong <juzhe.zhong@rivai.ai>
Date:   Fri Dec 1 16:09:59 2023 +0800

    RISC-V: Support highpart overlap for indexed load with SRC EEW < DEST EEW

    Leverage previous approach.

    Before this patch:

    .L5:
            add     a3,s0,s2
            add     a4,s6,s2
            add     a5,s7,s2
            vsetvli zero,s0,e64,m8,ta,ma
            vle8.v  v4,0(s2)
            vle8.v  v3,0(a3)
            mv      s2,s1
            vle8.v  v2,0(a4)
            vle8.v  v1,0(a5)
            nop
            vluxei8.v       v8,(s1),v4
            vs8r.v  v8,0(sp)              ---> spill
            vluxei8.v       v8,(s1),v3
            vluxei8.v       v16,(s1),v2
            vluxei8.v       v24,(s1),v1
            nop
            vmv.x.s a1,v8
            vl8re64.v       v8,0(sp)     ---> reload
            vmv.x.s a3,v24
            vmv.x.s a2,v16
            vmv.x.s a0,v8
            add     s1,s1,s5
            call    sumation
            add     s3,s3,a0
            bgeu    s4,s1,.L5

    After this patch:

    .L5:
            add     a3,s0,s2
            add     a4,s6,s2
            add     a5,s7,s2
            vsetvli zero,s0,e64,m8,ta,ma
            vle8.v  v15,0(s2)
            vle8.v  v23,0(a3)
            mv      s2,s1
            vle8.v  v31,0(a4)
            vle8.v  v7,0(a5)
            vluxei8.v       v8,(s1),v15
            vluxei8.v       v16,(s1),v23
            vluxei8.v       v24,(s1),v31
            vluxei8.v       v0,(s1),v7
            vmv.x.s a3,v0
            vmv.x.s a2,v24
            vmv.x.s a1,v16
            vmv.x.s a0,v8
            add     s1,s1,s5
            call    sumation
            add     s3,s3,a0
            bgeu    s4,s1,.L5

            PR target/112431

    gcc/ChangeLog:

            * config/riscv/vector.md: Support highpart overlap for indexed
load.

    gcc/testsuite/ChangeLog:

            * gcc.target/riscv/rvv/base/pr112431-28.c: New test.
            * gcc.target/riscv/rvv/base/pr112431-29.c: New test.
            * gcc.target/riscv/rvv/base/pr112431-30.c: New test.
            * gcc.target/riscv/rvv/base/pr112431-31.c: New test.
            * gcc.target/riscv/rvv/base/pr112431-32.c: New test.
            * gcc.target/riscv/rvv/base/pr112431-33.c: New test.