[PATCH] Fix ICE during insv expansion (PR rtl-optimization/70174)

[Richard Biener]

On Fri, 11 Mar 2016, Jakub Jelinek wrote:

> Hi!
> 
> The following testcase ICEs on i?86/x86_64 and aarch64, because gen_lowpart
> (pointer to gen_lowpart_general at that spot) doesn't want to handle
> SUBREG of SYMBOL_REF.  Fixed by using a variant that doesn't ICE and forcing
> the operand into a register if it can't be optimized without generating
> instructions.  This is similar to the case a few lines above, where we also
> force_reg if simplify_subreg failed.
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

Ok.

Thanks,
Richard.

> 2016-03-11  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR rtl-optimization/70174
> 	* expmed.c (store_bit_field_using_insv): Use gen_lowpart_if_possible
> 	followed by gen_lowpart on force_reg instead of just gen_lowpart.
> 
> 	* gcc.dg/pr70174.c: New test.
> 
> --- gcc/expmed.c.jj	2016-02-11 20:28:51.000000000 +0100
> +++ gcc/expmed.c	2016-03-11 10:40:27.258719168 +0100
> @@ -658,24 +658,28 @@ store_bit_field_using_insv (const extrac
>      {
>        if (GET_MODE_BITSIZE (GET_MODE (value)) >= bitsize)
>  	{
> +	  rtx tmp;
>  	  /* Optimization: Don't bother really extending VALUE
>  	     if it has all the bits we will actually use.  However,
>  	     if we must narrow it, be sure we do it correctly.  */
>  
>  	  if (GET_MODE_SIZE (GET_MODE (value)) < GET_MODE_SIZE (op_mode))
>  	    {
> -	      rtx tmp;
> -
>  	      tmp = simplify_subreg (op_mode, value1, GET_MODE (value), 0);
>  	      if (! tmp)
>  		tmp = simplify_gen_subreg (op_mode,
>  					   force_reg (GET_MODE (value),
>  						      value1),
>  					   GET_MODE (value), 0);
> -	      value1 = tmp;
>  	    }
>  	  else
> -	    value1 = gen_lowpart (op_mode, value1);
> +	    {
> +	      tmp = gen_lowpart_if_possible (op_mode, value1);
> +	      if (! tmp)
> +		tmp = gen_lowpart (op_mode, force_reg (GET_MODE (value),
> +						       value1));
> +	    }
> +	  value1 = tmp;
>  	}
>        else if (CONST_INT_P (value))
>  	value1 = gen_int_mode (INTVAL (value), op_mode);
> --- gcc/testsuite/gcc.dg/pr70174.c.jj	2016-03-11 10:42:45.914894656 +0100
> +++ gcc/testsuite/gcc.dg/pr70174.c	2016-03-11 10:42:31.000000000 +0100
> @@ -0,0 +1,11 @@
> +/* PR rtl-optimization/70174 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +
> +struct S { int f : 4; } a;
> +  
> +void
> +foo (void)
> +{ 
> +  a.f = foo;	/* { dg-warning "assignment makes integer from pointer without a cast" } */
> +}
> 
> 	Jakub
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)