[Bug target/92207] [10 Regression] pr36449.C fails on arm after r277179

[clyon at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92207

--- Comment #6 from Christophe Lyon <clyon at gcc dot gnu.org> ---
In particular, the execution continues after the last block dumped by qemu:
0x00018e40:  e5974008  ldr      r4, [r7, #8]
0x00018e44:  e0898008  add      r8, sb, r8
0x00018e48:  e3888001  orr      r8, r8, #1
0x00018e4c:  e5848004  str      r8, [r4, #4]
0x00018e50:  eaffff14  b        #0x18aa8

I set a breakpoint at 0x00018e40, then single-step until the crash:
=> 0x18e40 <_malloc_r+1732>:    ldr     r4, [r7, #8]
=> 0x18e44 <_malloc_r+1736>:    add     r8, r9, r8
=> 0x18e48 <_malloc_r+1740>:    orr     r8, r8, #1
=> 0x18e4c <_malloc_r+1744>:    str     r8, [r4, #4]
=> 0x18e50 <_malloc_r+1748>:    b       0x18aa8 <_malloc_r+812>
=> 0x18aa8 <_malloc_r+812>:     ldr     r3, [r10, #44]  ; 0x2c
=> 0x18aac <_malloc_r+816>:     cmp     r3, r1
=> 0x18ab0 <_malloc_r+820>:     ldr     r3, [r10, #48]  ; 0x30
=> 0x18ab4 <_malloc_r+824>:     strcc   r1, [r10, #44]  ; 0x2c
=> 0x18ab8 <_malloc_r+828>:     cmp     r3, r1
=> 0x18abc <_malloc_r+832>:     strcc   r1, [r10, #48]  ; 0x30
=> 0x18ac0 <_malloc_r+836>:     bic     r8, r8, #3
=> 0x18ac4 <_malloc_r+840>:     sub     r3, r8, r5
=> 0x18ac8 <_malloc_r+844>:     cmp     r3, #15
=> 0x18acc <_malloc_r+848>:     movgt   r2, #0
=> 0x18ad0 <_malloc_r+852>:     movle   r2, #1
=> 0x18ad4 <_malloc_r+856>:     cmp     r5, r8
=> 0x18ad8 <_malloc_r+860>:     orrhi   r2, r2, #1
=> 0x18adc <_malloc_r+864>:     cmp     r2, #0
=> 0x18ae0 <_malloc_r+868>:     beq     0x18ba4 <_malloc_r+1064>
=> 0x18ba4 <_malloc_r+1064>:    add     r2, r4, r5
=> 0x18ba8 <_malloc_r+1068>:    orr     r3, r3, #1
=> 0x18bac <_malloc_r+1072>:    orr     r5, r5, #1
=> 0x18bb0 <_malloc_r+1076>:    str     r5, [r4, #4]
=> 0x18bb4 <_malloc_r+1080>:    mov     r0, r6
=> 0x18bb8 <_malloc_r+1084>:    str     r2, [r7, #8]
=> 0x18bbc <_malloc_r+1088>:    add     r4, r4, #8
=> 0x18bc0 <_malloc_r+1092>:    str     r3, [r2, #4]
(gdb) p /x $r2
$1 = 0x804a568
(gdb) si

Program received signal SIGSEGV, Segmentation fault.
0x00018bc0 in _malloc_r (reent_ptr=0x49098 <impure_data>, bytes=<optimized
out>)
    at
/tmp/7992549.tmpdir/aci-gcc-fsf/sources/newlib/newlib/libc/stdlib/mallocr.c:2592
2592    in
/tmp/7992549.tmpdir/aci-gcc-fsf/sources/newlib/newlib/libc/stdlib/mallocr.c