On Tue, 28 Jun 2016, Jakub Jelinek wrote:
> Hi!
>
> This is just first small step towards this PR.
> It brings the ADDR_EXPR of DECL_P bases roughly on the same level as
> SSA_NAMEs pointers - so get_stridx_plus_constant works for them, and
> more importantly, before this patch there was a very severe bug in
> addr_stridxptr (missing list = list->next; in the loop), which meant that
> inside of a single decl we were tracking at most one string length, rather
> than the former 16 (or now 32) limit.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok.
Thanks,
Richard.
> As a follow-up, I'd like to introduce string length at least N, where we
> don't know the exact string length, but we know there are no '\0' chars
> within N bytes.
>
> 2016-06-28 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/71625
> * tree-ssa-strlen.c (get_addr_stridx): Add PTR argument. Assume list
> is sorted by ascending list->offset. If PTR is non-NULL and there is
> previous strinfo, call get_stridx_plus_constant.
> (get_stridx): Pass exp as second argument to get_addr_stridx.
> (addr_stridxptr): Add missing list = list->next, so that there can be
> more than one entries in the list. Bump limit from 16 to 32. Ensure
> the list is sorted by ascending list->offset.
> (get_stridx_plus_constant): Adjust so that it can be also called with
> ADDR_EXPR instead of SSA_NAME as PTR.
> (handle_char_store): Pass NULL_TREE as second argument to
> get_addr_stridx.
>
> * gcc.dg/strlenopt-28.c: New test.
>
> --- gcc/tree-ssa-strlen.c.jj 2016-06-28 10:21:22.103693623 +0200
> +++ gcc/tree-ssa-strlen.c 2016-06-28 13:41:56.797718522 +0200
> @@ -159,10 +159,10 @@ get_strinfo (int idx)
> /* Helper function for get_stridx. */
>
> static int
> -get_addr_stridx (tree exp)
> +get_addr_stridx (tree exp, tree ptr)
> {
> HOST_WIDE_INT off;
> - struct stridxlist *list;
> + struct stridxlist *list, *last = NULL;
> tree base;
>
> if (!decl_to_stridxlist_htab)
> @@ -180,9 +180,22 @@ get_addr_stridx (tree exp)
> {
> if (list->offset == off)
> return list->idx;
> + if (list->offset > off)
> + return 0;
> + last = list;
> list = list->next;
> }
> while (list);
> +
> + if (ptr && last && last->idx > 0)
> + {
> + strinfo *si = get_strinfo (last->idx);
> + if (si
> + && si->length
> + && TREE_CODE (si->length) == INTEGER_CST
> + && compare_tree_int (si->length, off - last->offset) != -1)
> + return get_stridx_plus_constant (si, off - last->offset, ptr);
> + }
> return 0;
> }
>
> @@ -234,7 +247,7 @@ get_stridx (tree exp)
>
> if (TREE_CODE (exp) == ADDR_EXPR)
> {
> - int idx = get_addr_stridx (TREE_OPERAND (exp, 0));
> + int idx = get_addr_stridx (TREE_OPERAND (exp, 0), exp);
> if (idx != 0)
> return idx;
> }
> @@ -304,15 +317,29 @@ addr_stridxptr (tree exp)
> if (existed)
> {
> int i;
> - for (i = 0; i < 16; i++)
> + stridxlist *before = NULL;
> + for (i = 0; i < 32; i++)
> {
> if (list->offset == off)
> return &list->idx;
> + if (list->offset > off && before == NULL)
> + before = list;
> if (list->next == NULL)
> break;
> + list = list->next;
> }
> - if (i == 16)
> + if (i == 32)
> return NULL;
> + if (before)
> + {
> + list = before;
> + before = XOBNEW (&stridx_obstack, struct stridxlist);
> + *before = *list;
> + list->next = before;
> + list->offset = off;
> + list->idx = 0;
> + return &list->idx;
> + }
> list->next = XOBNEW (&stridx_obstack, struct stridxlist);
> list = list->next;
> }
> @@ -613,9 +640,7 @@ verify_related_strinfos (strinfo *origsi
> static int
> get_stridx_plus_constant (strinfo *basesi, HOST_WIDE_INT off, tree ptr)
> {
> - gcc_checking_assert (TREE_CODE (ptr) == SSA_NAME);
> -
> - if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ptr))
> + if (TREE_CODE (ptr) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ptr))
> return 0;
>
> if (basesi->length == NULL_TREE
> @@ -633,7 +658,8 @@ get_stridx_plus_constant (strinfo *bases
> || TREE_CODE (si->length) != INTEGER_CST)
> return 0;
>
> - if (ssa_ver_to_stridx.length () <= SSA_NAME_VERSION (ptr))
> + if (TREE_CODE (ptr) == SSA_NAME
> + && ssa_ver_to_stridx.length () <= SSA_NAME_VERSION (ptr))
> ssa_ver_to_stridx.safe_grow_cleared (num_ssa_names);
>
> gcc_checking_assert (compare_tree_int (si->length, off) != -1);
> @@ -651,6 +677,7 @@ get_stridx_plus_constant (strinfo *bases
> {
> if (r == 0)
> {
> + gcc_assert (TREE_CODE (ptr) == SSA_NAME);
> ssa_ver_to_stridx[SSA_NAME_VERSION (ptr)] = si->idx;
> return si->idx;
> }
> @@ -2063,7 +2090,7 @@ handle_char_store (gimple_stmt_iterator
> }
> }
> else
> - idx = get_addr_stridx (lhs);
> + idx = get_addr_stridx (lhs, NULL_TREE);
>
> if (idx > 0)
> {
> --- gcc/testsuite/gcc.dg/strlenopt-28.c.jj 2016-06-28 13:57:06.768016510
> +0200
> +++ gcc/testsuite/gcc.dg/strlenopt-28.c 2016-06-28 13:55:01.000000000
> +0200
> @@ -0,0 +1,59 @@
> +/* { dg-do run } */
> +/* { dg-options "-O2 -fdump-tree-strlen" } */
> +
> +#include "strlenopt.h"
> +
> +volatile int v;
> +
> +size_t
> +f1 (void)
> +{
> + char a[30];
> + v += 1;
> + memcpy (a, "1234567", 8);
> + memcpy (a + 7, "89abcdefg", 10);
> + memcpy (a + 16, "h", 2);
> + return strlen (a); // This strlen should be optimized into 17.
> +}
> +
> +size_t
> +f2 (void)
> +{
> + char a[30];
> + v += 2;
> + strcpy (a, "1234567");
> + strcpy (a + 7, "89abcdefg");
> + strcpy (a + 16, "h");
> + return strlen (a); // This strlen should be optimized into 17.
> +}
> +
> +size_t
> +f3 (char *a)
> +{
> + v += 3;
> + memcpy (a, "1234567", 8);
> + memcpy (a + 7, "89abcdefg", 10);
> + memcpy (a + 16, "h", 2);
> + return strlen (a); // This strlen should be optimized into 17.
> +}
> +
> +size_t
> +f4 (char *a)
> +{
> + v += 4;
> + strcpy (a, "1234567");
> + strcpy (a + 7, "89abcdefg");
> + strcpy (a + 16, "h");
> + return strlen (a); // This strlen should be optimized into 17.
> +}
> +
> +int
> +main ()
> +{
> + char a[30];
> + if (f1 () != 17 || f2 () != 17 || f3 (a) != 17 || f4 (a) != 17)
> + abort ();
> + return 0;
> +}
> +
> +/* { dg-final { scan-tree-dump-times "strlen \\(" 0 "strlen" } } */
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
