Re: [PATCH] i386.c: Initialize function pointers to NULL to prevent, -Wmaybe-uninitialized

[Jakub Jelinek]

On Wed, Nov 23, 2016 at 11:06:23AM +0100, Martin Liška wrote:
> I see broken bootstrap due to:
> 
> .././../gcc/config/i386/i386.c: In function ‘rtx_def* 
> ix86_expand_builtin(tree, rtx, rtx, machine_mode, int)’:
> .././../gcc/config/i386/i386.c:38407:18: error: ‘fcn’ may be used 
> uninitialized in this function [-Werror=maybe-uninitialized]
>         emit_insn (fcn (target, accum, wide_reg, mem));
>         ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Thus I'm suggesting to initialize the variable (and 2 which are used in a 
> very similar manner) to NULL.
> 
> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.

That is not very relevant for i386.c change, is it?

> 2016-11-22  Martin Liska  <mli...@suse.cz>
> 
>       * config/i386/i386.c: Initialize function pointers to NULL.
> ---
>  gcc/config/i386/i386.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 25f0446..a373fcf 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -38218,9 +38218,9 @@ rdseed_step:
>        && fcode <= IX86_BUILTIN__BDESC_ARGS2_LAST)
>      {
>        i = fcode - IX86_BUILTIN__BDESC_ARGS2_FIRST;
> -      rtx (*fcn) (rtx, rtx, rtx, rtx);
> -      rtx (*fcn_mask) (rtx, rtx, rtx, rtx, rtx);
> -      rtx (*fcn_maskz) (rtx, rtx, rtx, rtx, rtx, rtx);
> +      rtx (*fcn) (rtx, rtx, rtx, rtx) = NULL;
> +      rtx (*fcn_mask) (rtx, rtx, rtx, rtx, rtx) = NULL;
> +      rtx (*fcn_maskz) (rtx, rtx, rtx, rtx, rtx, rtx) = NULL;
>        int masked = 1;
>        machine_mode mode, wide_mode, nar_mode;

      nar_mode  = V4SFmode;
      mode      = V16SFmode;   
      wide_mode = V64SFmode;
      fcn_mask  = gen_avx5124fmaddps_4fmaddps_mask;
      fcn_maskz = gen_avx5124fmaddps_4fmaddps_maskz;

follows this immediately, so there is no point in setting fcn_mask
and fcn_maskz to NULL.

        Jakub