On Wed, Apr 25, 2012 at 12:14 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> Hi!
>
> We have a splitter for reg1 = reg2 & 0xffffffff, but only if regnums
> are different. But movl %edi, %edi is a cheaper variant of
> andq $0xffffffff, %rdi even with the same register and doesn't clobber
> flags, so this patch attempts to expand it as a zero extension early.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2012-04-25 Jakub Jelinek <ja...@redhat.com>
>
> PR target/53110
> * config/i386/i386.md (and<mode>3): For andq $0xffffffff, reg
> instead expand it as zero extension.
>
> --- gcc/config/i386/i386.md.jj 2012-04-25 12:14:54.000000000 +0200
> +++ gcc/config/i386/i386.md 2012-04-25 14:50:48.708925963 +0200
> @@ -7694,7 +7694,17 @@ (define_expand "and<mode>3"
> (and:SWIM (match_operand:SWIM 1 "nonimmediate_operand")
> (match_operand:SWIM 2 "<general_szext_operand>")))]
> ""
> - "ix86_expand_binary_operator (AND, <MODE>mode, operands); DONE;")
> +{
> + if (<MODE>mode == DImode
> + && GET_CODE (operands[2]) == CONST_INT
> + && INTVAL (operands[2]) == (HOST_WIDE_INT) 0xffffffff
> + && REG_P (operands[1]))
> + emit_insn (gen_zero_extendsidi2 (operands[0],
> + gen_lowpart (SImode, operands[1])));
> + else
> + ix86_expand_binary_operator (AND, <MODE>mode, operands);
> + DONE;
> +})
>
> (define_insn "*anddi_1"
> [(set (match_operand:DI 0 "nonimmediate_operand" "=r,rm,r,r")
>
> Jakub
Can it be backported to 4.7 branch? It also fixed:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53961
on hjl/x32/gcc-4_7-branch.
Thanks.
--
H.J.
