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re PR rtl-optimization/17791 (doloop can produce wrong code causes Ada bootstrap failure)

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PR rtl-optimization/17791
	* loop-doloop.c (doloop_modify): Take number of iterations as
	argument.
	(doloop_optimize): Extend or shorten the number of iterations
	when changing mode of counter register.
	* loop-iv.c (lowpart_subreg): Export.
	* rtl.h (lowpart_subreg): Declare.

From-SVN: r88668
This commit is contained in:
Zdenek Dvorak 2004-10-07 08:20:34 +02:00 committed by Zdenek Dvorak
parent 1313b31fbb
commit a82bbcbbbe
4 changed files with 53 additions and 10 deletions
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10
gcc/ChangeLog
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@ -1,3 +1,13 @@
2004-10-07 Zdenek Dvorak <dvorakz@suse.cz>
PR rtl-optimization/17791
* loop-doloop.c (doloop_modify): Take number of iterations as
argument.
(doloop_optimize): Extend or shorten the number of iterations
when changing mode of counter register.
* loop-iv.c (lowpart_subreg): Export.
* rtl.h (lowpart_subreg): Declare.
2004-10-07 Zdenek Dvorak <dvorakz@suse.cz>
PR tree-optimization/17806

47
gcc/loop-doloop.c
View File

@ -257,20 +257,21 @@ add_test (rtx cond, basic_block bb, basic_block dest)
describes the loop, DESC describes the number of iterations of the
loop, and DOLOOP_INSN is the low-overhead looping insn to emit at the
end of the loop. CONDITION is the condition separated from the
DOLOOP_SEQ. */
DOLOOP_SEQ. COUNT is the number of iterations of the LOOP. */
static void
doloop_modify (struct loop *loop, struct niter_desc *desc,
rtx doloop_seq, rtx condition)
rtx doloop_seq, rtx condition, rtx count)
{
rtx counter_reg;
rtx count, tmp, noloop = NULL_RTX;
rtx tmp, noloop = NULL_RTX;
rtx sequence;
rtx jump_insn;
rtx jump_label;
int nonneg = 0, irr;
bool increment_count;
basic_block loop_end = desc->out_edge->src;
enum machine_mode mode;
jump_insn = BB_END (loop_end);
@ -291,8 +292,8 @@ doloop_modify (struct loop *loop, struct niter_desc *desc,
counter_reg = XEXP (condition, 0);
if (GET_CODE (counter_reg) == PLUS)
counter_reg = XEXP (counter_reg, 0);
mode = GET_MODE (counter_reg);
count = copy_rtx (desc->niter_expr);
increment_count = false;
switch (GET_CODE (condition))
{
@ -323,7 +324,7 @@ doloop_modify (struct loop *loop, struct niter_desc *desc,
Note that the maximum value loaded is iterations_max - 1. */
if (desc->niter_max
<= ((unsigned HOST_WIDEST_INT) 1
<< (GET_MODE_BITSIZE (GET_MODE (counter_reg)) - 1)))
<< (GET_MODE_BITSIZE (mode) - 1)))
nonneg = 1;
break;
@ -333,7 +334,7 @@ doloop_modify (struct loop *loop, struct niter_desc *desc,
}
if (increment_count)
count = simplify_gen_binary (PLUS, desc->mode, count, const1_rtx);
count = simplify_gen_binary (PLUS, mode, count, const1_rtx);
/* Insert initialization of the count register into the loop header. */
start_sequence ();
@ -438,12 +439,14 @@ doloop_optimize (struct loop *loop)
{
enum machine_mode mode;
rtx doloop_seq, doloop_pat, doloop_reg;
rtx iterations;
rtx iterations, count;
rtx iterations_max;
rtx start_label;
rtx condition;
unsigned level, est_niter;
struct niter_desc *desc;
unsigned word_mode_size;
unsigned HOST_WIDE_INT word_mode_max;
if (dump_file)
fprintf (dump_file, "Doloop: Processing loop %d.\n", loop->num);
@ -481,6 +484,7 @@ doloop_optimize (struct loop *loop)
return false;
}
count = copy_rtx (desc->niter_expr);
iterations = desc->const_iter ? desc->niter_expr : const0_rtx;
iterations_max = GEN_INT (desc->niter_max);
level = get_loop_level (loop) + 1;
@ -492,8 +496,33 @@ doloop_optimize (struct loop *loop)
doloop_reg = gen_reg_rtx (mode);
doloop_seq = gen_doloop_end (doloop_reg, iterations, iterations_max,
GEN_INT (level), start_label);
if (! doloop_seq && mode != word_mode)
word_mode_size = GET_MODE_BITSIZE (word_mode);
word_mode_max
= ((unsigned HOST_WIDE_INT) 1 << (word_mode_size - 1) << 1) - 1;
if (! doloop_seq
&& mode != word_mode
/* Before trying mode different from the one in that # of iterations is
computed, we must be sure that the number of iterations fits into
the new mode. */
&& (word_mode_size >= GET_MODE_BITSIZE (mode)
|| desc->niter_max <= word_mode_max))
{
if (word_mode_size > GET_MODE_BITSIZE (mode))
{
count = simplify_gen_unary (ZERO_EXTEND, word_mode,
iterations, mode);
iterations = simplify_gen_unary (ZERO_EXTEND, word_mode,
iterations, mode);
iterations_max = simplify_gen_unary (ZERO_EXTEND, word_mode,
iterations_max, mode);
}
else
{
count = lowpart_subreg (word_mode, count, mode);
iterations = lowpart_subreg (word_mode, iterations, mode);
iterations_max = lowpart_subreg (word_mode, iterations_max, mode);
}
PUT_MODE (doloop_reg, word_mode);
doloop_seq = gen_doloop_end (doloop_reg, iterations, iterations_max,
GEN_INT (level), start_label);
@ -528,7 +557,7 @@ doloop_optimize (struct loop *loop)
return false;
}
doloop_modify (loop, desc, doloop_seq, condition);
doloop_modify (loop, desc, doloop_seq, condition, count);
return true;
}

2
gcc/loop-iv.c
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@ -156,7 +156,7 @@ assign_luids (basic_block bb)
/* Generates a subreg to get the least significant part of EXPR (in mode
INNER_MODE) to OUTER_MODE. */
static rtx
rtx
lowpart_subreg (enum machine_mode outer_mode, rtx expr,
enum machine_mode inner_mode)
{

4
gcc/rtl.h
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@ -1432,6 +1432,10 @@ extern void push_to_full_sequence (rtx, rtx);
extern rtx immed_double_const (HOST_WIDE_INT, HOST_WIDE_INT,
enum machine_mode);
/* In loop-iv.c */
extern rtx lowpart_subreg (enum machine_mode, rtx, enum machine_mode);
/* In varasm.c */
extern rtx force_const_mem (enum machine_mode, rtx);