echo "void f(){volatile long long a=123;__sync_val_compare_and_swap(&a,3,4);}" | gcc -O2 -mthumb -mfloat-abi=softfp -x c -Wall -dA -S - -o -

        .syntax unified
        .arch armv7-a
        .eabi_attribute 27, 3   @ Tag_ABI_HardFP_use
        .fpu neon
        .eabi_attribute 20, 1   @ Tag_ABI_FP_denormal
        .eabi_attribute 21, 1   @ Tag_ABI_FP_exceptions
        .eabi_attribute 23, 3   @ Tag_ABI_FP_number_model
        .eabi_attribute 24, 1   @ Tag_ABI_align8_needed
        .eabi_attribute 25, 1   @ Tag_ABI_align8_preserved
        .eabi_attribute 26, 2   @ Tag_ABI_enum_size
        .eabi_attribute 30, 2   @ Tag_ABI_optimization_goals
        .eabi_attribute 34, 1   @ Tag_CPU_unaligned_access
        .eabi_attribute 18, 4   @ Tag_ABI_PCS_wchar_t
        .file   ""
        .text
        .align  2
        .global f
        .thumb
        .thumb_func
        .type   f, %function
f:
        @ args = 0, pretend = 0, frame = 8
        @ frame_needed = 0, uses_anonymous_args = 0
        @ link register save eliminated.
@ BLOCK 2 freq:10000 seq:0
@ PRED: ENTRY [100.0%]  (fallthru)
        push    {r4, r5}
        fldd    d16, .L5        @ int
        sub     sp, sp, #8
        add     r4, sp, #8
        fstmdbd r4!, {d16}      @ int
        dmb     sy
        movs    r2, #4
@ SUCC: 3 [100.0%]  (fallthru,can_fallthru)
        movs    r3, #0
@ BLOCK 3 freq:10000 seq:1
@ PRED: 2 [100.0%]  (fallthru,can_fallthru) 4 [1.0%]  (dfs_back,can_fallthru)
.L2:
        ldrexd  r0, r1, [r4]
        cmp     r1, #0
        it eq
        cmpeq   r0, #3
@ SUCC: 5 [1.0%]  (can_fallthru,loop_exit) 4 [99.0%]  (fallthru,can_fallthru)
        bne     .L3
@ BLOCK 4 freq:9901 seq:2
@ PRED: 3 [99.0%]  (fallthru,can_fallthru)
        strexd  r5, r2, r3, [r4]
        cmp     r5, #0
@ SUCC: 3 [1.0%]  (dfs_back,can_fallthru) 5 [99.0%]  (fallthru,can_fallthru,loop_exit)
        bne     .L2
@ BLOCK 5 freq:9902 seq:3
@ PRED: 3 [1.0%]  (can_fallthru,loop_exit) 4 [99.0%]  (fallthru,can_fallthru,loop_exit)
.L3:
        dmb     sy
@ SUCC: EXIT [100.0%]
        add     sp, sp, #8
        pop     {r4, r5}
        bx      lr
.L6:
        .align  3
.L5:
        .word   123
        .word   0
        .size   f, .-f
        .ident  "GCC: (Linaro GCC 4.7-2012.07) 4.7.2 20120701 (prerelease)"
        .section        .note.GNU-stack,"",%progbits

Attribute Section: aeabi
File Attributes
  Tag_CPU_name: "CORTEX-A8"
  Tag_CPU_arch: v7
  Tag_CPU_arch_profile: Application
  Tag_ARM_ISA_use: Yes
  Tag_THUMB_ISA_use: Thumb-2
  Tag_FP_arch: VFPv3
  Tag_ABI_PCS_wchar_t: 4
  Tag_ABI_FP_denormal: Needed
  Tag_ABI_FP_exceptions: Needed
  Tag_ABI_FP_number_model: IEEE 754
  Tag_ABI_align_needed: 8-byte
  Tag_ABI_enum_size: int
  Tag_ABI_HardFP_use: SP and DP
  Tag_Virtualization_use: TrustZone