Jakub,
Is it important to have correct value for length attribute for Big Cores?
As I new this attribute is used for code layout alignment.
2014-08-15 15:54 GMT+04:00 Jakub Jelinek <ja...@redhat.com>:
> On Fri, Aug 15, 2014 at 03:45:33PM +0400, Yuri Rumyantsev wrote:
>> gcc/ChangeLog
>> 2014-08-15 Yuri Rumyantsev <ysrum...@gmail.com>
>>
>> PR target/62011
>> * config/i386/i386-protos.h (ix86_avoid_false_dep_for_bm): New function
>> prototype.
>> * config/i386/i386.c (ix86_avoid_false_dep_for_bm): New function.
>> * config/i386/i386.h (TARGET_AVOID_FALSE_DEP_FOR_BM) New macros.
>> * config/i386/i386.md (ctz<mode>2, clz<mode>2_lzcnt, popcount<mode>2,
>> *popcount<mode>2_cmp, *popcountsi2_cmp_zext): Output zeroing
>> destination register for unary bit-manipulation instructions
>> if required.
>> * config/i386/x86-tune.def (X86_TUNE_AVOID_FALSE_DEP_FOR_BM): New.
>
> --- config/i386/i386.md (revision 213842)
> +++ config/i386/i386.md (working copy)
> @@ -12111,7 +12111,13 @@
> ""
> {
> if (TARGET_BMI)
> - return "tzcnt{<imodesuffix>}\t{%1, %0|%0, %1}";
> + {
> + if (ix86_avoid_false_dep_for_bm (insn, operands))
> + return "xor{<imodesuffix>}\t%0, %0\n\t"
> + "tzcnt{<imodesuffix>}\t{%1, %0|%0, %1}";
> + else
> + return "tzcnt{<imodesuffix>}\t{%1, %0|%0, %1}";
> + }
> else if (optimize_function_for_size_p (cfun))
> ;
> else if (TARGET_GENERIC)
>
> etc., this will make lenght attribute incorrect though.
>
> Jakub
