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From: "hjl.tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/103066]
 __sync_val_compare_and_swap/__sync_bool_compare_and_swap aren't optimized
Date: Fri, 05 Nov 2021 13:07:40 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103066

--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> ---
Instead of generating:

        movl    f(%rip), %eax
.L2:
        movd    %eax, %xmm0
        addss   .LC0(%rip), %xmm0
        movd    %xmm0, %edx
        lock cmpxchgl   %edx, f(%rip)
        jne     .L2
        ret

we want

        movl    f(%rip), %eax
.L2:
        movd    %eax, %xmm0
        addss   .LC0(%rip), %xmm0
        movd    %xmm0, %edx
        cmpl    f(%rip), %eax
        jne     .L2
        lock cmpxchgl   %edx, f(%rip)
        jne     .L2
        ret=