On Sun, Jul 15, 2012 at 1:56 AM, H.J. Lu <hjl.to...@gmail.com> wrote:
> On Wed, Apr 25, 2012 at 12:14 PM, Jakub Jelinek <ja...@redhat.com> wrote:
>
>> 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.
I have backported the patch to 4.7 branch. OTOH, those LEA patterns
are really in the need of some cleanup in the future.
Uros.
