OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

re PR tree-optimization/21520 (missing PRE opportunity with operand after operand)

Browse Source 
Fix PR tree-optimization/21520
	* tree-ssa-pre.c (phi_translate): Use fully_constant_expression
	to attempt to fold constants.

From-SVN: r99632
This commit is contained in:
Steven Bosscher 2005-05-12 22:13:00 +00:00 committed by Daniel Berlin
parent 02f20dc3fd
commit 0995a441f5
3 changed files with 57 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
gcc/ChangeLog
View File

@ -1,3 +1,9 @@
2005-05-12 Steven Bosscher <stevenb@suse.de>
Fix PR tree-optimization/21520
* tree-ssa-pre.c (phi_translate): Use fully_constant_expression
to attempt to fold constants.
2005-05-12 Kaz Kojima <kkojima@gcc.gnu.org>
* config/sh/sh.c: Declare the prototype of sh_adjust_unroll_max

14
gcc/testsuite/gcc.c-torture/compile/pr21532.c Normal file
View File

@ -0,0 +1,14 @@
int
bar (unsigned char key)
{
unsigned char buf[sizeof (unsigned long)+2];
unsigned char b;
unsigned char *buf_ = buf + 1;
for (b = 8; b != 0; b--)
buf_[b] = key >> b;
return foo (b);
}

54
gcc/tree-ssa-pre.c
View File

@ -842,6 +842,19 @@ debug_value_set (value_set_t set, const char *setname, int blockindex)
print_value_set (stderr, set, setname, blockindex);
}
/* Return the folded version of T if T, when folded, is a gimple
min_invariant. Otherwise, return T. */
static tree
fully_constant_expression (tree t)
{
tree folded;
folded = fold (t);
if (folded && is_gimple_min_invariant (folded))
return folded;
return t;
}
/* Translate EXPR using phis in PHIBLOCK, so that it has the values of
the phis in PRED. Return NULL if we can't find a leader for each
part of the translated expression. */
@ -889,12 +902,22 @@ phi_translate (tree expr, value_set_t set, basic_block pred,
return NULL;
if (newop1 != oldop1 || newop2 != oldop2)
{
tree t;
newexpr = pool_alloc (binary_node_pool);
memcpy (newexpr, expr, tree_size (expr));
create_tree_ann (newexpr);
TREE_OPERAND (newexpr, 0) = newop1 == oldop1 ? oldop1 : get_value_handle (newop1);
TREE_OPERAND (newexpr, 1) = newop2 == oldop2 ? oldop2 : get_value_handle (newop2);
vn_lookup_or_add (newexpr, NULL);
t = fully_constant_expression (newexpr);
if (t != newexpr)
{
pool_free (binary_node_pool, newexpr);
newexpr = t;
}
else
{
create_tree_ann (newexpr);
vn_lookup_or_add (newexpr, NULL);
}
expr = newexpr;
phi_trans_add (oldexpr, newexpr, pred);
}
@ -913,11 +936,21 @@ phi_translate (tree expr, value_set_t set, basic_block pred,
return NULL;
if (newop1 != oldop1)
{
tree t;
newexpr = pool_alloc (unary_node_pool);
memcpy (newexpr, expr, tree_size (expr));
create_tree_ann (newexpr);
TREE_OPERAND (newexpr, 0) = get_value_handle (newop1);
vn_lookup_or_add (newexpr, NULL);
t = fully_constant_expression (newexpr);
if (t != newexpr)
{
pool_free (unary_node_pool, newexpr);
newexpr = t;
}
else
{
create_tree_ann (newexpr);
vn_lookup_or_add (newexpr, NULL);
}
expr = newexpr;
phi_trans_add (oldexpr, newexpr, pred);
}
@ -1412,19 +1445,6 @@ create_expression_by_pieces (basic_block block, tree expr, tree stmts)
return name;
}
/* Return the folded version of T if T, when folded, is a gimple
min_invariant. Otherwise, return T. */
static tree
fully_constant_expression (tree t)
{
tree folded;
folded = fold (t);
if (folded && is_gimple_min_invariant (folded))
return folded;
return t;
}
/* Insert the to-be-made-available values of NODE for each predecessor, stored
in AVAIL, into the predecessors of BLOCK, and merge the result with a phi
node, given the same value handle as NODE. The prefix of the phi node is