[llvm-commits] [llvm] r40970 - /llvm/trunk/lib/Target/X86/X86RegisterInfo.td

[Christopher Lamb]

Evan,

I don't think that this change is working quite correctly, and may  
not be needed, given the way that the subreg code uses those values.  
This is currently causing regressions in dejagnu.

The register classes in the SubRegClassList are used when new subreg  
vregs are created. The key is that the register class be valid for  
the register-register mappings in the SubRegSet of the corresponding  
index, that is that the all the subregs of the class must be members  
of the SubRegClass, not that the sets must be equal.

Every subreg of GR16_ is a member of GR8, and every subreg of GR32_  
is properly a member of GR8 or GR16.
--
Chris

On Aug 9, 2007, at 11:05 AM, Evan Cheng wrote:

> Author: evancheng
> Date: Thu Aug  9 13:05:17 2007
> New Revision: 40970
>
> URL: http://llvm.org/viewvc/llvm-project?rev=40970&view=rev
> Log:
> GR16_ sub-register class should be GR8_, not GR8. That is, it  
> should only be 8-bit registers in 32-bit mode. Ditto for GR32_.
>
> Modified:
>     llvm/trunk/lib/Target/X86/X86RegisterInfo.td
>
> Modified: llvm/trunk/lib/Target/X86/X86RegisterInfo.td
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/ 
> X86RegisterInfo.td?rev=40970&r1=40969&r2=40970&view=diff
>
> ====================================================================== 
> ========
> --- llvm/trunk/lib/Target/X86/X86RegisterInfo.td (original)
> +++ llvm/trunk/lib/Target/X86/X86RegisterInfo.td Thu Aug  9  
> 13:05:17 2007
> @@ -417,13 +417,14 @@
>  }
>
>
> -// GR16, GR32 subclasses which contain registers that have R8 sub- 
> registers.
> +// GR16, GR32 subclasses which contain registers that have GR8 sub- 
> registers.
>  // These should only be used for 32-bit mode.
> +def GR8_ : RegisterClass<"X86", [i8], 8, [AL, CL, DL, BL, AH, CH,  
> DH, BH]>;
>  def GR16_ : RegisterClass<"X86", [i16], 16, [AX, CX, DX, BX]> {
> -  let SubRegClassList = [GR8];
> +  let SubRegClassList = [GR8_];
>  }
>  def GR32_ : RegisterClass<"X86", [i32], 32, [EAX, ECX, EDX, EBX]> {
> -  let SubRegClassList = [GR8, GR16];
> +  let SubRegClassList = [GR8_, GR16_];
>  }
>
>  // Scalar SSE2 floating point registers.
>
>
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--
Christopher Lamb



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