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

[Jan Hubicka]

> Hi!
> 
> I'd like to ping this patch (with the sizeof (c) -> sizeof (c) / sizeof (c[0])
> testsuite fix Andreas pointed out).
> 
> Thanks!
> 
> On Tue, Dec 10, 2019 at 10:57:35AM +0100, Jakub Jelinek wrote:
> > 2019-12-10  Jakub Jelinek  <ja...@redhat.com>
> > 
> >     PR target/92841
> >     * config/i386/i386.md (*stack_protect_set_2_<mode>,
> >     *stack_protect_set_3): New define_insns and corresponding
> >     define_peephole2s.
> > 
> >     * gcc.target/i386/pr92841.c: New test.

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?

Honza