[PATCH] fold-const: Fix up ((1 << x) & y) != 0 folding for vectors [PR99225]

[Richard Biener]

On Wed, 24 Feb 2021, Jakub Jelinek wrote:

> Hi!
> 
> This optimization was written purely with scalar integers in mind,
> can work fine even with vectors, but we can't use build_int_cst but
> need to use build_one_cst instead.
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

OK.

Richard.
 
> 2021-02-24  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR tree-optimization/99225
> 	* fold-const.c (fold_binary_loc) <case NE_EXPR>: In (x & (1 << y)) != 0
> 	to ((x >> y) & 1) != 0 simplifications use build_one_cst instead of
> 	build_int_cst (..., 1).  Formatting fixes.
> 
> 	* gcc.c-torture/compile/pr99225.c: New test.
> 
> --- gcc/fold-const.c.jj	2021-02-23 09:49:40.000000000 +0100
> +++ gcc/fold-const.c	2021-02-23 19:53:33.143763292 +0100
> @@ -12044,23 +12044,23 @@ fold_binary_loc (location_t loc, enum tr
>  	      && integer_onep (TREE_OPERAND (arg00, 0)))
>  	    {
>  	      tree tem = fold_build2_loc (loc, RSHIFT_EXPR, TREE_TYPE (arg00),
> -				      arg01, TREE_OPERAND (arg00, 1));
> +					  arg01, TREE_OPERAND (arg00, 1));
>  	      tem = fold_build2_loc (loc, BIT_AND_EXPR, TREE_TYPE (arg0), tem,
> -				 build_int_cst (TREE_TYPE (arg0), 1));
> +				     build_one_cst (TREE_TYPE (arg0)));
>  	      return fold_build2_loc (loc, code, type,
> -				  fold_convert_loc (loc, TREE_TYPE (arg1), tem),
> -				  arg1);
> +				      fold_convert_loc (loc, TREE_TYPE (arg1),
> +							tem), arg1);
>  	    }
>  	  else if (TREE_CODE (arg01) == LSHIFT_EXPR
>  		   && integer_onep (TREE_OPERAND (arg01, 0)))
>  	    {
>  	      tree tem = fold_build2_loc (loc, RSHIFT_EXPR, TREE_TYPE (arg01),
> -				      arg00, TREE_OPERAND (arg01, 1));
> +					  arg00, TREE_OPERAND (arg01, 1));
>  	      tem = fold_build2_loc (loc, BIT_AND_EXPR, TREE_TYPE (arg0), tem,
> -				 build_int_cst (TREE_TYPE (arg0), 1));
> +				     build_one_cst (TREE_TYPE (arg0)));
>  	      return fold_build2_loc (loc, code, type,
> -				  fold_convert_loc (loc, TREE_TYPE (arg1), tem),
> -				  arg1);
> +				      fold_convert_loc (loc, TREE_TYPE (arg1),
> +							tem), arg1);
>  	    }
>  	}
>  
> --- gcc/testsuite/gcc.c-torture/compile/pr99225.c.jj	2021-02-23 20:12:01.825464969 +0100
> +++ gcc/testsuite/gcc.c-torture/compile/pr99225.c	2021-02-23 20:11:45.962640464 +0100
> @@ -0,0 +1,31 @@
> +/* PR tree-optimization/99225 */
> +
> +typedef int V __attribute__((vector_size (4 * sizeof (int))));
> +
> +void
> +foo (V *x)
> +{
> +  x[2] = (x[0] & (1 << x[1])) != 0;
> +}
> +
> +void
> +bar (V *x)
> +{
> +  x[2] = ((1 << x[1]) & x[0]) != 0;
> +}
> +
> +void
> +baz (V *x)
> +{
> +  V a = 1 << x[1];
> +  V b = a & x[0];
> +  x[2] = b != 0;
> +}
> +
> +void
> +qux (V *x)
> +{
> +  V a = 1 << x[1];
> +  V b = x[0] & a;
> +  x[2] = b != 0;
> +}
> 
> 	Jakub
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)