------- Comment #19 from ubizjak at gmail dot com 2008-11-20 21:37 -------
Hm, rdx gets corrupted:
check2848va:
.LFB0:
.cfi_startproc
movq %rsi, %rcx # tmp73,
leaq 8(%rsp), %rax #,
(+) movq %rdx, -40(%rsp) #,
shrq $32, %rcx #,
cmpl %esi, s2848(%rip) # tmp73, s2848.a
>>> movq -80(%rsp), %rdx #, tmp74
movq %rax, -112(%rsp) #, <variable>.overflow_arg_area
leaq -56(%rsp), %rax #,
movq %rsi, -48(%rsp) #,
movl $8, -120(%rsp) #, <variable>.gp_offset
movq %rsi, -88(%rsp) # tmp70,
movq %rax, -104(%rsp) #, <variable>.reg_save_area
movq %rsi, -72(%rsp) # tmp73, arg
movq %rdx, -64(%rsp) # tmp74, arg
je .L4 #,
addl $1, fails(%rip) #, fails
.L4:
cmpl %ecx, s2848+4(%rip) # arg$b$real, s2848.b
setne %cl #, tmp79
(++) cmpl %edx, s2848+8(%rip) # arg$b$imag, s2848.b
setne %al #, tmp82
orb %al, %cl # tmp82, tmp79
je .L6 #,
addl $1, fails(%rip) #, fails
rdx is saved at the point of (+), corrupted at ">>>" and this corrupted value
is used at (++). The insn at ">>>" just falls in the insn stream from the sky,
it is not present if "a" is changed to "unsigned long" in S2848 structure.
In case when "a" is changed to "unsigned long", testcase works OK. The testcase
also works when insn at ">>>" is removed.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38151
