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* unroll.c (unroll_loop): Correct special exit cases. 

From-SVN: r47499
This commit is contained in:
Zoltan Hidvegi 2001-11-30 23:27:52 +00:00 committed by David Edelsohn
parent 38875aba47
commit d2384b42b7
2 changed files with 35 additions and 8 deletions
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4
gcc/ChangeLog
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@ -1,3 +1,7 @@
2001-11-30 Zoltan Hidvegi <hzoli@hzoli.2y.net>
* unroll.c (unroll_loop): Correct special exit cases.
2001-11-30 Stephane Carrez <Stephane.Carrez@sun.com>
* config/sparc/sparc.c (DF_MODES_NO_S): Fix pr/3623, define to

39
gcc/unroll.c
View File

@ -901,6 +901,9 @@ unroll_loop (loop, insn_count, strength_reduce_p)
rtx diff;
rtx *labels;
int abs_inc, neg_inc;
enum rtx_code cc = loop_info->comparison_code;
int less_p = (cc == LE || cc == LEU || cc == LT || cc == LTU);
int unsigned_p = (cc == LEU || cc == GEU || cc == LTU || cc == GTU);
map->reg_map = (rtx *) xmalloc (maxregnum * sizeof (rtx));
@ -933,11 +936,25 @@ unroll_loop (loop, insn_count, strength_reduce_p)
a constant.
We must copy the final and initial values here to avoid
improperly shared rtl. */
improperly shared rtl.
diff = expand_simple_binop (mode, MINUS, copy_rtx (final_value),
copy_rtx (initial_value), NULL_RTX, 0,
OPTAB_LIB_WIDEN);
We have to deal with for (i = 0; --i < 6;) type loops.
For such loops the real final value is the first time the
loop variable overflows, so the diff we calculate is the
distance from the overflow value. This is 0 or ~0 for
unsigned loops depending on the direction, or INT_MAX,
INT_MAX+1 for signed loops. We really do not need the
exact value, since we are only interested in the diff
modulo the increment, and the increment is a power of 2,
so we can pretend that the overflow value is 0/~0. */
if (cc == NE || less_p != neg_inc)
diff = expand_simple_binop (mode, MINUS, copy_rtx (final_value),
copy_rtx (initial_value), NULL_RTX, 0,
OPTAB_LIB_WIDEN);
else
diff = expand_simple_unop (mode, neg_inc ? NOT : NEG,
copy_rtx (initial_value), NULL_RTX, 0);
/* Now calculate (diff % (unroll * abs (increment))) by using an
and instruction. */
@ -958,11 +975,17 @@ unroll_loop (loop, insn_count, strength_reduce_p)
case. This check does not apply if the loop has a NE
comparison at the end. */
if (loop_info->comparison_code != NE)
if (cc != NE)
{
emit_cmp_and_jump_insns (initial_value, final_value,
neg_inc ? LE : GE,
NULL_RTX, mode, 0, labels[1]);
rtx incremented_initval;
incremented_initval = expand_simple_binop (mode, PLUS,
initial_value,
increment,
NULL_RTX, 0,
OPTAB_LIB_WIDEN);
emit_cmp_and_jump_insns (incremented_initval, final_value,
less_p ? GE : LE, NULL_RTX,
mode, unsigned_p, labels[1]);
predict_insn_def (get_last_insn (), PRED_LOOP_CONDITION,
NOT_TAKEN);
JUMP_LABEL (get_last_insn ()) = labels[1];