Re: [Qemu-devel] Re: [PATCH 5/7] tcg-i386: Implement deposit operation.

[Richard Henderson]

On 01/10/2011 10:37 AM, Aurelien Jarno wrote:
>>      mov     y,x
>>      deposit y,y,x,8,8
>>
>> So I could simply put a tcg_abort there.  It would be up to whoever
>> improves the register allocator to provide some mechanism for a
>> backend to allocate a scratch.  What do you think?
>>
> 
> Do you have a way to trigger this problem? or a dump of the ops and asm
> output?

IN: 
0x408120c4:  rlwimi  r4,r4,8,16,23

OP:
 ---- 0x408120c4
 deposit_i32 r4,r4,r4,8,8
 goto_tb $0x0
 movi_i32 nip,$0x408120c8
 exit_tb $0x7fbb00ca5758

OUT: [size=52]
0x60294380:  mov    0x10(%r14),%ebp
0x60294384:  mov    %ebp,%ebx
0x60294386:  ror    $0x8,%ebp
0x60294389:  shrd   $0x8,%ebx,%ebp
0x6029438d:  rol    $0x10,%ebp
0x60294390:  mov    %ebp,0x10(%r14)
0x60294394:  jmpq   0x60294399
0x60294399:  mov    $0x408120c8,%ebp
0x6029439e:  mov    %ebp,0x25c(%r14)
0x602943a5:  mov    $0x7fbb00ca5758,%rax
0x602943af:  jmpq   0x622b772e

That should do it.  This is present in linux-user-test ppc/ls.
This output still contains that allocate-a-scratch path.


r~