[LLVMdev] [x86 codegen] 3DNow! intrinsics not behaving as expected.

[Michael Spencer]

On Thu, Apr 14, 2011 at 5:37 PM, Chris Lattner <clattner at apple.com> wrote:
>
> On Apr 14, 2011, at 12:47 PM, Eli Friedman wrote:
>
>>> I looked at the program using a debugger, and the pfadd instruction is
>>> executed correctly and the MMX register contains the correct values.
>>> The code that prepares the stack for the printf call seems to be
>>> messing it up.
>>
>> I would call that "user error"; basically, using MMX instructions
>> messes up the FP stack, and we assume the user is smart enough to make
>> sure the two don't mix.
>
> More specifically, if you use MMX/3dNow intrinsics, you have to call "emms" at ABI boundaries.
>
> -Chris
>

Ok, now it makes sense. Thanks. Now that I know this is right, are
these patches ok to commit? Or should I post them to the llvm-commits,
and cfe-commits list?

- Michael Spencer