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Re: [PATCH] Improve andq $0xffffffff, %reg handling (PR target/53110)


On Mon, Apr 30, 2012 at 02:54:05PM +0200, Uros Bizjak wrote:
> > My recent changes to zero_extend expanders should handle this
> > automatically, and will undo generation of zero_extend pattern. Please
> > see zero_extend<mode>si2_and expander, and how it handles
> > TARGET_ZERO_EXTEND_WITH_AND targets.
> 
> Attached patch implements this idea. In addition, it fixes the
> splitter to not change output mode of zero_extension from HImode and
> QImode from DImode to SImode. Although they generate the same
> instruction, I think we should better keep original mode here.

Thanks.  I was trying this morning slightly different patch for the same,
but strangely it failed bootstrap, and didn't get around to analysing
why a mem store had (zero_extend (subreg (reg))) on a RHS.

> +  operands[1] = gen_lowpart (mode, operands[1]);
> +
> +  if (GET_MODE (operands[0]) == DImode)
> +    insn = (mode == SImode)
> +	   ? gen_zero_extendsidi2
> +	   : (mode == HImode)
> +	   ? gen_zero_extendhidi2
> +	   : gen_zero_extendqidi2;
> +  else if (GET_MODE (operands[0]) == SImode)
> +    insn = (mode == HImode)
> +	   ? gen_zero_extendhisi2
> +	   : gen_zero_extendqisi2;
> +  else if (GET_MODE (operands[0]) == HImode)
> +    insn = gen_zero_extendqihi2;
>    else
> -    ix86_expand_binary_operator (AND, <MODE>mode, operands);
> +    gcc_unreachable ();
> +
> +  emit_insn (insn (operands[0], operands[1]));

IMHO you should use <MODE>mode instead of GET_MODE (operands[0])
in all of the above, then the compiler can actually optimize
it at compile time.

	Jakub


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