[llvm-commits] [llvm] r141274 - in /llvm/trunk: lib/Target/X86/X86InstrInfo.td lib/Target/X86/X86RegisterInfo.td test/MC/X86/x86-32.s test/MC/X86/x86-64.s utils/TableGen/EDEmitter.cpp utils/TableGen/X86RecognizableInstr.cpp

[Jakob Stoklund Olesen]

On Oct 5, 2011, at 11:44 PM, Craig Topper wrote:

> Author: ctopper
> Date: Thu Oct  6 01:44:41 2011
> New Revision: 141274
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=141274&view=rev
> Log:
> Fix assembling of xchg %eax, %eax to not use the NOP encoding of 0x90. This was done by creating a new register group that excludes AX registers. Fixes PR10345. Also added aliases for flipping the order of the operands of xchg <reg>, %eax.

Please add comments explaining why this is necessary.