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tree-tailcall.c (process_assignment): Don't check if a multiplication or an addition are already present.

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2009-09-21  Giuseppe Scrivano <gscrivano@gnu.org>

	* tree-tailcall.c (process_assignment): Don't check if a multiplication
	or an addition are already present.
	(find_tail_calls): Combine multiple additions and multiplications.
	(adjust_accumulator_values): Emit accumulators.

testsuite:
2009-09-21  Giuseppe Scrivano <gscrivano@gnu.org>

	* gcc.dg/tree-ssa/tailrecursion-6.c: New file.

From-SVN: r151935
This commit is contained in:
Giuseppe Scrivano 2009-09-21 16:41:58 +00:00 • committed by Paolo Bonzini
parent 334738b440
commit d9334061ea
4 changed files with 52 additions and 13 deletions
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7
gcc/ChangeLog
View file

@ -1,3 +1,10 @@
2009-09-21 Giuseppe Scrivano <gscrivano@gnu.org>
* tree-tailcall.c (process_assignment): Don't check if a multiplication
or an addition are already present.
(find_tail_calls): Combine multiple additions and multiplications.
(adjust_accumulator_values): Emit accumulators.
2009-09-21 Kai Tietz <kai.tietz@onevision.com>
* config/i386/i386.c (ix86_expand_epilogue): Adjust offset for

4
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,7 @@
2009-09-21 Giuseppe Scrivano <gscrivano@gnu.org>
* gcc.dg/tree-ssa/tailrecursion-6.c: New file.
2009-09-21 Jason Merrill <jason@redhat.com>
PR c++/41421

12
gcc/testsuite/gcc.dg/tree-ssa/tailrecursion-6.c Normal file
View file

@ -0,0 +1,12 @@
/* { dg-do compile } */
/* { dg-options "-O1 -foptimize-sibling-calls -fdump-tree-tailr-details" } */
int
foo (int a)
{
if (a)
return a * (2 * (foo (a - 1))) + a + 1;
else
return 0;
}
/* { dg-final { scan-tree-dump-times "Eliminated tail recursion" 1 "tailr1"} } */
/* { dg-final { cleanup-tree-dump "tailr\[1-2\]" } } */

42
gcc/tree-tailcall.c
View file

@ -326,22 +326,11 @@ process_assignment (gimple stmt, gimple_stmt_iterator call, tree *m,
switch (code)
{
case PLUS_EXPR:
/* There should be no previous addition. TODO -- it should be fairly
straightforward to lift this restriction -- just allow storing
more complicated expressions in *A, and gimplify it in
adjust_accumulator_values. */
if (*a)
return false;
*a = non_ass_var;
*ass_var = dest;
return true;
case MULT_EXPR:
/* Similar remark applies here. Handling multiplication after addition
is just slightly more complicated -- we need to multiply both *A and
*M. */
if (*a || *m)
return false;
*m = non_ass_var;
*ass_var = dest;
return true;
@ -484,6 +473,8 @@ find_tail_calls (basic_block bb, struct tailcall **ret)
agsi = gsi;
while (1)
{
tree tmp_a = NULL_TREE;
tree tmp_m = NULL_TREE;
gsi_next (&agsi);
while (gsi_end_p (agsi))
@ -508,8 +499,26 @@ find_tail_calls (basic_block bb, struct tailcall **ret)
return;
/* This is a gimple assign. */
if (! process_assignment (stmt, gsi, &m, &a, &ass_var))
if (! process_assignment (stmt, gsi, &tmp_m, &tmp_a, &ass_var))
return;
if (tmp_a)
{
if (a)
a = fold_build2 (PLUS_EXPR, TREE_TYPE (tmp_a), a, tmp_a);
else
a = tmp_a;
}
if (tmp_m)
{
if (m)
m = fold_build2 (MULT_EXPR, TREE_TYPE (tmp_m), m, tmp_m);
else
m = tmp_m;
if (a)
a = fold_build2 (MULT_EXPR, TREE_TYPE (tmp_m), a, tmp_m);
}
}
/* See if this is a tail call we can handle. */
@ -605,8 +614,15 @@ update_accumulator_with_ops (enum tree_code code, tree acc, tree op1,
static void
adjust_accumulator_values (gimple_stmt_iterator gsi, tree m, tree a, edge back)
{
tree var, a_acc_arg = a_acc, m_acc_arg = m_acc;
tree var, a_acc_arg, m_acc_arg;
if (m)
m = force_gimple_operand_gsi (&gsi, m, true, NULL, true, GSI_SAME_STMT);
if (a)
a = force_gimple_operand_gsi (&gsi, a, true, NULL, true, GSI_SAME_STMT);
a_acc_arg = a_acc;
m_acc_arg = m_acc;
if (a)
{
if (m_acc)