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From: "avi at scylladb dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug rtl-optimization/104484] -freorder-block-and-partition not
 splitting into sections with __builin_expect()
Date: Thu, 10 Feb 2022 13:02:09 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104484

--- Comment #2 from Avi Kivity <avi at scylladb dot com> ---
(In reply to Andrew Pinski from comment #1)
> But the assembly output does not make sense to the code you gave either.


Apart from the missing .section directives, I didn't notice anything odd. M=
aybe
movl/testl could be optimized into cmpl.

Ah, I moved this code from C++ so the function signatures are bad, should be
fun(void). With the signatures adjusted, I get

light:
.LFB2:
        .cfi_startproc
        subq    $8, %rsp
        .cfi_def_cfa_offset 16
        call    fun
        movl    f1(%rip), %edx
        testl   %edx, %edx
        jne     .L8
.L6:
        addq    $8, %rsp
        .cfi_remember_state
        .cfi_def_cfa_offset 8
        jmp     fun
        .p2align 4,,10
        .p2align 3
.L8:
        .cfi_restore_state
        movl    f2(%rip), %eax
        testl   %eax, %eax
        je      .L6
        call    very_heavy
        jmp     .L6
        .cfi_endproc


Which still misses the .section directives and the peephole optimization to
merge movl/testl.=