[llvm-commits] [llvm] r58230 - in /llvm/trunk: include/llvm/Target/TargetInstrInfo.h lib/CodeGen/PreAllocSplitting.cpp lib/Target/X86/X86InstrInfo.cpp lib/Target/X86/X86InstrInfo.h lib/Target/X86/X86RegisterInfo.h test/CodeGen/X86/pre-split7.ll

[Evan Cheng]

On Oct 27, 2008, at 11:14 AM, Chris Lattner wrote:

>
> On Oct 27, 2008, at 12:14 AM, Evan Cheng wrote:
>
>> Author: evancheng
>> Date: Mon Oct 27 02:14:50 2008
>> New Revision: 58230
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=58230&view=rev
>> Log:
>> For now, don't split live intervals around x87 stack register
>> barriers. FpGET_ST0_80 must be right after a call instruction (and
>> ADJCALLSTACKUP) so we need to find a way to prevent reload of x87
>> registers between them.
>
> Eww... This seems exactly like the "copy instruction that clobbers
> flags" problem,

Yep. Except this is not modeled in the machine instruction level at  
all. Once we figure out a way to deal with it, this patch can go away.

Evan

>
>
> -Chris
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