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From: "lis8215 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/111384] missed optimization: GCC adds extra
 any extend when storing subreg#0 multiple times
Date: Tue, 12 Sep 2023 13:10:24 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D111384

--- Comment #2 from Siarhei Volkau <lis8215 at gmail dot com> ---
Well what the godbolt says with -O2 -fomit-frame-pointer.

ARM:
        uxth    r0, r0          @ << zero extend
        strh    r0, [r1]
        strh    r0, [r2]
        bx      lr

ARM64:
        and     w0, w0, 65535   @ << zero extend
        strh    w0, [x1]
        strh    w0, [x2]
        ret

MIPS64:
        andi    $4,$4,0xffff    @ << zero extend
        sh      $4,0($5)
        jr      $31
        sh      $4,0($6)

MRISC32:
        shuf    r1, r1, #2888   @ << zero extend
        sth     r1, [r2]
        sth     r1, [r3]
        ret

RISC-V:
        slli    a0,a0,16        @ << zero extend
        srli    a0,a0,16        @ << zero extend
        sh      a0,0(a1)
        sh      a0,0(a2)
        ret

RISC-V (64-bit):
        slli    a0,a0,48        @ << zero extend
        srli    a0,a0,48        @ << zero extend
        sh      a0,0(a1)
        sh      a0,0(a2)
        ret

Xtensa ESP32:
        entry   sp, 32
        extui   a2, a2, 0, 16   @ << zero extend
        s16i    a2, a3, 0
        s16i    a2, a4, 0
        retw.n

Loongarch64:
        bstrpick.w      $r4,$r4,15,0  @ << zero extend
        st.h    $r4,$r5,0
        st.h    $r4,$r6,0
        jr      $r1

MIPS:
        andi    $4,$4,0xffff    @ << zero extend
        sh      $4,0($5)
        jr      $31
        sh      $4,0($6)

SH:
        extu.w  r4,r4           @ << zero extend
        mov.w   r4,@r5
        rts=20=20=20=20=20
        mov.w   r4,@r6


Other available at godbolt (x86-64/Power/Power64/s390) unaffected.=