Patch ping (was Re: [PATCH] Oprimize stack_protect_set_1_<mode> followed by a move to the same register (PR target/92841))

[Jakub Jelinek]

On Thu, Dec 19, 2019 at 04:01:31PM +0100, Jan Hubicka wrote:
> I now get build failure of Firefox with LTO due to:
> 
> movabsq $.LC12, %rax
> 
> which is output by:
> 
> (insn:TI 468 3 849 2 (parallel [                                                
>             (set (mem/v/f/c:DI (plus:DI (reg/f:DI 6 bp)                         
>                         (const_int -56 [0xffffffffffffffc8])) [1 D.22910+0 S8 A64])
>                 (unspec:DI [                                                    
>                         (mem/v/f:DI (const_int 40 [0x28]) [0 MEM[(<address-space-1> long unsigned int *)40B]+0 S8 A64 AS1])
>                     ] UNSPEC_SP_SET))                                           
>             (set (reg:DI 0 ax [157])                                            
>                 (symbol_ref/f:DI ("*.LC12") [flags 0x2]  <var_decl 0x7ffff56ac870 *.LC12>))
>             (clobber (reg:CC 17 flags))                                         
>         ]) 1042 {*stack_protect_set_3}                                          
>      (expr_list:REG_UNUSED (reg:CC 17 flags)                                    
>         (nil)))                                                                 
> 
> I suppose we need to be more careful about the symbolic operands for
> movabs?

Is that -fPIC or -fPIE or -fno-pic?
What were the two insns before peephole2?

	Jakub