On Thu, 25 Apr 2013, Jakub Jelinek wrote:
> Hi!
>
> This patch adds folding of constant arguments v>> and v<<, which helps to
> optimize the testcase from the PR back into constant store after vectorized
> loop is unrolled.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok.
Thanks,
Richard.
> 2013-04-25 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/57051
> * fold-const.c (const_binop): Handle VEC_LSHIFT_EXPR
> and VEC_RSHIFT_EXPR if shift count is a multiple of element
> bitsize.
>
> --- gcc/fold-const.c.jj 2013-04-12 10:16:25.000000000 +0200
> +++ gcc/fold-const.c 2013-04-24 12:37:11.789122719 +0200
> @@ -1380,17 +1380,42 @@ const_binop (enum tree_code code, tree a
> int count = TYPE_VECTOR_SUBPARTS (type), i;
> tree *elts = XALLOCAVEC (tree, count);
>
> - for (i = 0; i < count; i++)
> + if (code == VEC_LSHIFT_EXPR
> + || code == VEC_RSHIFT_EXPR)
> {
> - tree elem1 = VECTOR_CST_ELT (arg1, i);
> -
> - elts[i] = const_binop (code, elem1, arg2);
> + if (!host_integerp (arg2, 1))
> + return NULL_TREE;
>
> - /* It is possible that const_binop cannot handle the given
> - code and return NULL_TREE */
> - if (elts[i] == NULL_TREE)
> + unsigned HOST_WIDE_INT shiftc = tree_low_cst (arg2, 1);
> + unsigned HOST_WIDE_INT outerc = tree_low_cst (TYPE_SIZE (type), 1);
> + unsigned HOST_WIDE_INT innerc
> + = tree_low_cst (TYPE_SIZE (TREE_TYPE (type)), 1);
> + if (shiftc >= outerc || (shiftc % innerc) != 0)
> return NULL_TREE;
> + int offset = shiftc / innerc;
> + if (code == VEC_LSHIFT_EXPR)
> + offset = -offset;
> + tree zero = build_zero_cst (TREE_TYPE (type));
> + for (i = 0; i < count; i++)
> + {
> + if (i + offset < 0 || i + offset >= count)
> + elts[i] = zero;
> + else
> + elts[i] = VECTOR_CST_ELT (arg1, i + offset);
> + }
> }
> + else
> + for (i = 0; i < count; i++)
> + {
> + tree elem1 = VECTOR_CST_ELT (arg1, i);
> +
> + elts[i] = const_binop (code, elem1, arg2);
> +
> + /* It is possible that const_binop cannot handle the given
> + code and return NULL_TREE */
> + if (elts[i] == NULL_TREE)
> + return NULL_TREE;
> + }
>
> return build_vector (type, elts);
> }
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend
