[Bug c/67242] Missing optimization with float

[f.boesing at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67242

--- Comment #2 from Frank <f.boesing at gmx dot de> ---
x86-64:



        .file   "bug.c"
        .section        .text.unlikely,"x"
.LCOLDB0:
        .text
.LHOTB0:
        .p2align 4,,15
        .globl  bug
        .def    bug;    .scl    2;      .type   32;     .endef
        .seh_proc       bug
bug:
        .seh_endprologue
        movl    $999, dummy(%rip)
        xorl    %eax, %eax
        .p2align 4,,10
.L2:
        pxor    %xmm0, %xmm0
        cvtsi2ss        %eax, %xmm0
        addl    $1, %eax
        cmpl    $1000, %eax
        jne     .L2
        movss   %xmm0, dummyfloat(%rip)
        movl    $1000, n(%rip)
        ret
        .seh_endproc
        .section        .text.unlikely,"x"
.LCOLDE0:
        .text
.LHOTE0:
        .comm   dummyfloat, 4, 2
        .comm   dummy, 4, 2
        .comm   n, 4, 2
        .ident  "GCC: (tdm64-1) 4.9.2"







arm-thumb, soft float:
        .cpu arm7tdmi
        .fpu softvfp
        .eabi_attribute 20, 1
        .eabi_attribute 21, 1
        .eabi_attribute 23, 3
        .eabi_attribute 24, 1
        .eabi_attribute 25, 1
        .eabi_attribute 26, 1
        .eabi_attribute 30, 2
        .eabi_attribute 34, 0
        .eabi_attribute 18, 4
        .code   16
        .file   "bug.c"
        .global __aeabi_i2f
        .text
        .align  2
        .global bug
        .code   16
        .thumb_func
        .type   bug, %function
bug:
        push    {r3, r4, r5, lr}
        mov     r5, #250
        mov     r4, #0
        ldr     r2, .L5
        ldr     r3, .L5+4
        str     r2, [r3]
        lsl     r5, r5, #2
.L2:
        mov     r0, r4
        add     r4, r4, #1
        bl      __aeabi_i2f
        cmp     r4, r5
        bne     .L2
        ldr     r3, .L5+8
        str     r0, [r3]
        ldr     r3, .L5+12
        @ sp needed
        str     r4, [r3]
        pop     {r3, r4, r5}
        pop     {r0}
        bx      r0
.L6:
        .align  2
.L5:
        .word   999
        .word   dummy
        .word   dummyfloat
        .word   n
        .size   bug, .-bug
        .comm   dummyfloat,4,4
        .comm   dummy,4,4
        .comm   n,4,4
        .ident  "GCC: (GNU Tools for ARM Embedded Processors) 4.9.3 20150529
(release) [ARM/embedded-4_9-branch revision 224288]"