[llvm-commits] [llvm] r49946 - /llvm/trunk/lib/Target/X86/X86InstrInfo.td

[Dan Gohman]

Don't forget about LXCHG64!

Dan

On Apr 18, 2008, at 6:20 PM, Evan Cheng wrote:
> Author: evancheng
> Date: Fri Apr 18 20:20:30 2008
> New Revision: 49946
>
> URL: http://llvm.org/viewvc/llvm-project?rev=49946&view=rev
> Log:
> xchg which references a memory operand does not need to lock prefix.  
> Atomicity is guaranteed.
>
> Modified:
>    llvm/trunk/lib/Target/X86/X86InstrInfo.td
>
> Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.td
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.td?rev=49946&r1=49945&r2=49946&view=diff
>
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> ======================================================================
> --- llvm/trunk/lib/Target/X86/X86InstrInfo.td (original)
> +++ llvm/trunk/lib/Target/X86/X86InstrInfo.td Fri Apr 18 20:20:30 2008
> @@ -2543,6 +2543,21 @@
> // Atomic support
> //
>
> +// Atomic swap. These are just normal xchg instructions. But since  
> a memory
> +// operand is referenced, the atomicity is ensured.
> +let Constraints = "$val = $dst", Defs = [EFLAGS] in {
> +def XCHG32rm : I<0x87, MRMSrcMem, (outs GR32:$dst), (ins i32mem: 
> $ptr, GR32:$val),
> +               "xchg{l}\t{$val, $ptr|$ptr, $val}",
> +               [(set GR32:$dst, (atomic_swap_32 addr:$ptr,  
> GR32:$val))]>;
> +def XCHG16rm : I<0x87, MRMSrcMem, (outs GR16:$dst), (ins i16mem: 
> $ptr, GR16:$val),
> +               "xchg{w}\t{$val, $ptr|$ptr, $val}",
> +               [(set GR16:$dst, (atomic_swap_16 addr:$ptr,  
> GR16:$val))]>,
> +                OpSize;
> +def XCHG8rm  : I<0x86, MRMSrcMem, (outs GR8:$dst), (ins i8mem:$ptr,  
> GR8:$val),
> +               "xchg{b}\t{$val, $ptr|$ptr, $val}",
> +               [(set GR8:$dst, (atomic_swap_8 addr:$ptr,  
> GR8:$val))]>;
> +}
> +
> // Atomic compare and swap.
> let Defs = [EAX, EFLAGS], Uses = [EAX] in {
> def LCMPXCHG32 : I<0xB1, MRMDestMem, (outs), (ins i32mem:$ptr,  
> GR32:$swap),
> @@ -2566,20 +2581,6 @@
>                [(X86cas addr:$ptr, GR8:$swap, 1)]>, TB, LOCK;
> }
>
> -// Atomic swap
> -let Constraints = "$val = $dst", Defs = [EFLAGS] in {
> -def LXCHG32 : I<0x87, MRMSrcMem, (outs GR32:$dst), (ins i32mem: 
> $ptr, GR32:$val),
> -               "lock xchg{l}\t{$val, $ptr|$ptr, $val}",
> -               [(set GR32:$dst, (atomic_swap_32 addr:$ptr,  
> GR32:$val))]>, LOCK;
> -def LXCHG16 : I<0x87, MRMSrcMem, (outs GR16:$dst), (ins i16mem: 
> $ptr, GR16:$val),
> -               "lock xchg{w}\t{$val, $ptr|$ptr, $val}",
> -               [(set GR16:$dst, (atomic_swap_16 addr:$ptr,  
> GR16:$val))]>,
> -                OpSize, LOCK;
> -def LXCHG8  : I<0x86, MRMSrcMem, (outs GR8:$dst), (ins i8mem:$ptr,  
> GR8:$val),
> -               "lock xchg{b}\t{$val, $ptr|$ptr, $val}",
> -               [(set GR8:$dst, (atomic_swap_8 addr:$ptr,  
> GR8:$val))]>, LOCK;
> -}
> -
> // Atomic exchange and add
> let Constraints = "$val = $dst", Defs = [EFLAGS] in {
> def LXADD32 : I<0xC1, MRMSrcMem, (outs GR32:$dst), (ins i32mem:$ptr,  
> GR32:$val),
>
>
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