[LLVMdev] movaps being generated despite alignment 1 being specified

Evan Cheng
Fri, 19 Oct 2007 06:56:38 -0000

On Oct 18, 2007, at 1:52 PM, Chuck Rose III wrote:

>
> Here are the instructions for evaluateDependents.  The JITter
> hasn’t compiled foo yet.  What’s confusing to me is why did my
> movups suddenly become a movaps?  All the stores and loads have
> align 1 on them.

Hi Chuck,

I believe this is a bug but am unable to reproduce it with the test
case you've provided. I should be able to see the same problem using
llc since the code generator is going through all the same passes.
The only difference should be the relocation model.

Please file a bug and provide us with a test case. You should be able
to set a break point somewhere in ExecutionEngine.cpp / JIT.cpp and
just dump out the bitcode with Module->dump() / print().

Evan

>
>
> …
>
> 15D10012  sub         esp,4Ch
>
> 15D10015  mov         eax,dword ptr [esp+60h]
>
> 15D10019  movups      xmm0,xmmword ptr [eax]
>
> 15D1001C  movaps      xmmword ptr [esp+8],xmm0    ß why did this
> become a movaps?
>
> 15D10021  movups      xmmword ptr [esp+28h],xmm0
>
> 15D10026  mov         esi,dword ptr [esp+58h]
>
> 15D1002A  mov         edi,dword ptr [esp+5Ch]
>
> 15D1002E  mov         dword ptr [esp],40000000h
>
> 15D10035  call        X86CompilationCallback (1335030h)
>
>
>
> Thanks for the help!
>
>
>
> Chuck.
>
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