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ifcvt.c (noce_init_if_info): New static function, broken out of noce_process_if_block.

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./:	* ifcvt.c (noce_init_if_info): New static function, broken out of
	noce_process_if_block.
	(noce_process_if_block): Call noce_init_if_info.
	(check_cond_move_block): New static function.
	(cond_move_process_if_block): New static function.
	(process_if_block): Call cond_move_process_if_block.
testsuite/:
	* gcc.target/i386/cmov6.c: New test.

From-SVN: r109717
This commit is contained in:
Ian Lance Taylor 2006-01-15 02:49:17 +00:00 • committed by Ian Lance Taylor
parent 7c514720e4
commit 5d1dcaa2c3
4 changed files with 317 additions and 28 deletions
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9
gcc/ChangeLog
View file

@ -1,3 +1,12 @@
2006-01-14 Ian Lance Taylor <ian@airs.com>
* ifcvt.c (noce_init_if_info): New static function, broken out of
noce_process_if_block.
(noce_process_if_block): Call noce_init_if_info.
(check_cond_move_block): New static function.
(cond_move_process_if_block): New static function.
(process_if_block): Call cond_move_process_if_block.
2006-01-15 Kazu Hirata <kazu@codesourcery.com>
* cselib.c (hash_table): Rename to cselib_hash_table.

310
gcc/ifcvt.c
View file

@ -2016,6 +2016,52 @@ noce_get_condition (rtx jump, rtx *earliest)
NULL_RTX, false, true);
}
/* Initialize for a simple IF-THEN or IF-THEN-ELSE block. We will not
be using conditional execution. Set some fields of IF_INFO based
on CE_INFO: test_bb, cond, jump, cond_earliest. Return TRUE if
things look OK. */
static int
noce_init_if_info (struct ce_if_block *ce_info, struct noce_if_info *if_info)
{
basic_block test_bb = ce_info->test_bb;
rtx cond, jump;
/* If test is comprised of && or || elements, don't handle it unless
it is the special case of && elements without an ELSE block. */
if (ce_info->num_multiple_test_blocks)
{
if (ce_info->else_bb || !ce_info->and_and_p)
return FALSE;
ce_info->test_bb = test_bb = ce_info->last_test_bb;
ce_info->num_multiple_test_blocks = 0;
ce_info->num_and_and_blocks = 0;
ce_info->num_or_or_blocks = 0;
}
/* If this is not a standard conditional jump, we can't parse it. */
jump = BB_END (test_bb);
cond = noce_get_condition (jump, &if_info->cond_earliest);
if (!cond)
return FALSE;
/* If the conditional jump is more than just a conditional
jump, then we can not do if-conversion on this block. */
if (! onlyjump_p (jump))
return FALSE;
/* We must be comparing objects whose modes imply the size. */
if (GET_MODE (XEXP (cond, 0)) == BLKmode)
return FALSE;
if_info->test_bb = test_bb;
if_info->cond = cond;
if_info->jump = jump;
return TRUE;
}
/* Return true if OP is ok for if-then-else processing. */
static int
@ -2111,33 +2157,11 @@ noce_process_if_block (struct ce_if_block * ce_info)
??? For future expansion, look for multiple X in such patterns. */
/* If test is comprised of && or || elements, don't handle it unless it is
the special case of && elements without an ELSE block. */
if (ce_info->num_multiple_test_blocks)
{
if (else_bb || ! ce_info->and_and_p)
return FALSE;
ce_info->test_bb = test_bb = ce_info->last_test_bb;
ce_info->num_multiple_test_blocks = 0;
ce_info->num_and_and_blocks = 0;
ce_info->num_or_or_blocks = 0;
}
/* If this is not a standard conditional jump, we can't parse it. */
jump = BB_END (test_bb);
cond = noce_get_condition (jump, &if_info.cond_earliest);
if (! cond)
if (!noce_init_if_info (ce_info, &if_info))
return FALSE;
/* If the conditional jump is more than just a conditional
jump, then we can not do if-conversion on this block. */
if (! onlyjump_p (jump))
return FALSE;
/* We must be comparing objects whose modes imply the size. */
if (GET_MODE (XEXP (cond, 0)) == BLKmode)
return FALSE;
cond = if_info.cond;
jump = if_info.jump;
/* Look for one of the potential sets. */
insn_a = first_active_insn (then_bb);
@ -2216,9 +2240,6 @@ noce_process_if_block (struct ce_if_block * ce_info)
return FALSE;
/* Set up the info block for our subroutines. */
if_info.test_bb = test_bb;
if_info.cond = cond;
if_info.jump = jump;
if_info.insn_a = insn_a;
if_info.insn_b = insn_b;
if_info.x = x;
@ -2340,6 +2361,235 @@ noce_process_if_block (struct ce_if_block * ce_info)
return TRUE;
}
/* Check whether a block is suitable for conditional move conversion.
Every insn must be a simple set of a register to a constant or a
register. For each assignment, store the value in the array VALS,
indexed by register number. COND is the condition we will
test. */
static int
check_cond_move_block (basic_block bb, rtx *vals, rtx cond)
{
rtx insn;
FOR_BB_INSNS (bb, insn)
{
rtx set, dest, src;
if (!INSN_P (insn) || JUMP_P (insn))
continue;
set = single_set (insn);
if (!set)
return FALSE;
dest = SET_DEST (set);
src = SET_SRC (set);
if (!REG_P (dest)
|| (SMALL_REGISTER_CLASSES && HARD_REGISTER_P (dest)))
return false;
if (!CONSTANT_P (src) && !register_operand (src, VOIDmode))
return FALSE;
if (side_effects_p (src) || side_effects_p (dest))
return FALSE;
if (may_trap_p (src) || may_trap_p (dest))
return FALSE;
/* Don't try to handle this if the destination register was
modified earlier in the block. */
if (vals[REGNO (dest)] != NULL)
return FALSE;
/* Don't try to handle this if the condition uses the
destination register. */
if (reg_overlap_mentioned_p (dest, cond))
return FALSE;
vals[REGNO (dest)] = src;
/* Don't try to handle this if the source register is modified
later in the block. */
if (!CONSTANT_P (src)
&& modified_between_p (src, insn, NEXT_INSN (BB_END (bb))))
return FALSE;
}
return TRUE;
}
/* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
using only conditional moves. Return TRUE if we were successful at
converting the block. */
static int
cond_move_process_if_block (struct ce_if_block *ce_info)
{
basic_block then_bb = ce_info->then_bb;
basic_block else_bb = ce_info->else_bb;
struct noce_if_info if_info;
rtx jump, cond, insn, seq, cond_arg0, cond_arg1, loc_insn;
int max_reg, size, c, i;
rtx *then_vals;
rtx *else_vals;
enum rtx_code code;
if (!HAVE_conditional_move || no_new_pseudos)
return FALSE;
memset (&if_info, 0, sizeof if_info);
if (!noce_init_if_info (ce_info, &if_info))
return FALSE;
cond = if_info.cond;
jump = if_info.jump;
/* Build a mapping for each block to the value used for each
register. */
max_reg = max_reg_num ();
size = (max_reg + 1) * sizeof (rtx);
then_vals = (rtx *) alloca (size);
else_vals = (rtx *) alloca (size);
memset (then_vals, 0, size);
memset (else_vals, 0, size);
/* Make sure the blocks are suitable. */
if (!check_cond_move_block (then_bb, then_vals, cond)
|| (else_bb && !check_cond_move_block (else_bb, else_vals, cond)))
return FALSE;
/* Make sure the blocks can be used together. If the same register
is set in both blocks, and is not set to a constant in both
cases, then both blocks must set it to the same register. We
have already verified that if it is set to a register, that the
source register does not change after the assignment. Also count
the number of registers set in only one of the blocks. */
c = 0;
for (i = 0; i <= max_reg; ++i)
{
if (!then_vals[i] && !else_vals[i])
continue;
if (!then_vals[i] || !else_vals[i])
++c;
else
{
if (!CONSTANT_P (then_vals[i])
&& !CONSTANT_P (else_vals[i])
&& !rtx_equal_p (then_vals[i], else_vals[i]))
return FALSE;
}
}
/* Make sure it is reasonable to convert this block. What matters
is the number of assignments currently made in only one of the
branches, since if we convert we are going to always execute
them. */
if (c > MAX_CONDITIONAL_EXECUTE)
return FALSE;
/* Emit the conditional moves. First do the then block, then do
anything left in the else blocks. */
code = GET_CODE (cond);
cond_arg0 = XEXP (cond, 0);
cond_arg1 = XEXP (cond, 1);
start_sequence ();
FOR_BB_INSNS (then_bb, insn)
{
rtx set, target, dest, t, e;
unsigned int regno;
if (!INSN_P (insn) || JUMP_P (insn))
continue;
set = single_set (insn);
gcc_assert (set && REG_P (SET_DEST (set)));
dest = SET_DEST (set);
regno = REGNO (dest);
t = then_vals[regno];
e = else_vals[regno];
gcc_assert (t);
if (!e)
e = dest;
target = noce_emit_cmove (&if_info, dest, code, cond_arg0, cond_arg1,
t, e);
if (!target)
{
end_sequence ();
return FALSE;
}
if (target != dest)
noce_emit_move_insn (dest, target);
}
if (else_bb)
{
FOR_BB_INSNS (else_bb, insn)
{
rtx set, target, dest;
unsigned int regno;
if (!INSN_P (insn) || JUMP_P (insn))
continue;
set = single_set (insn);
gcc_assert (set && REG_P (SET_DEST (set)));
dest = SET_DEST (set);
regno = REGNO (dest);
/* If this register was set in the then block, we already
handled this case above. */
if (then_vals[regno])
continue;
gcc_assert (else_vals[regno]);
target = noce_emit_cmove (&if_info, dest, code, cond_arg0, cond_arg1,
dest, else_vals[regno]);
if (!target)
{
end_sequence ();
return FALSE;
}
if (target != dest)
noce_emit_move_insn (dest, target);
}
}
seq = end_ifcvt_sequence (&if_info);
if (!seq)
return FALSE;
loc_insn = first_active_insn (then_bb);
if (!loc_insn)
{
loc_insn = first_active_insn (else_bb);
gcc_assert (loc_insn);
}
emit_insn_before_setloc (seq, jump, INSN_LOCATOR (loc_insn));
FOR_BB_INSNS (then_bb, insn)
if (INSN_P (insn) && !JUMP_P (insn))
delete_insn (insn);
if (else_bb)
{
FOR_BB_INSNS (else_bb, insn)
if (INSN_P (insn) && !JUMP_P (insn))
delete_insn (insn);
}
delete_insn (jump);
merge_if_block (ce_info);
return TRUE;
}
/* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
straight line code. Return true if successful. */
@ -2351,6 +2601,10 @@ process_if_block (struct ce_if_block * ce_info)
&& noce_process_if_block (ce_info))
return TRUE;
if (HAVE_conditional_move
&& cond_move_process_if_block (ce_info))
return TRUE;
if (HAVE_conditional_execution && reload_completed)
{
/* If we have && and || tests, try to first handle combining the && and

4
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,7 @@
2006-01-14 Ian Lance Taylor <ian@airs.com>
* gcc.target/i386/cmov6.c: New test.
2006-01-14 Mark Mitchell <mark@codesourcery.com>
PR c++/25663

22
gcc/testsuite/gcc.target/i386/cmov6.c Normal file
View file

@ -0,0 +1,22 @@
/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
/* { dg-options "-O2 -march=i686" } */
/* { dg-final { scan-assembler "cmov\[^6\]" } } */
/* Verify that blocks are converted to conditional moves. */
extern int bar (int, int);
int foo (int c, int d, int e)
{
int a, b;
if (c)
{
a = 10;
b = d;
}
else
{
a = e;
b = 20;
}
return bar (a, b);
}