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jump.c (duplicate_loop_exit_test): Better test for jumps entering the loop; create loop pre_header.

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* jump.c (duplicate_loop_exit_test): Better test for jumps
	entering the loop; create loop pre_header.

From-SVN: r44512
This commit is contained in:
Jan Hubicka 2001-07-31 15:36:12 +02:00 committed by Jan Hubicka
parent 20dde49d1f
commit 940b29aa63
2 changed files with 17 additions and 3 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
Tue Jul 31 15:33:27 CEST 2001 Jan Hubicka <jh@suse.cz>
* jump.c (duplicate_loop_exit_test): Better test for jumps
entering the loop; create loop pre_header.
2001-07-31 Hartmut Penner <hpenner@de.ibm.com>
* doc/install.texi: Add s390 and s390x as new targets.

15
gcc/jump.c
View File

@ -305,6 +305,7 @@ duplicate_loop_exit_test (loop_start)
rtx lastexit;
int max_reg = max_reg_num ();
rtx *reg_map = 0;
rtx loop_pre_header_label;
/* Scan the exit code. We do not perform this optimization if any insn:
@ -405,6 +406,7 @@ duplicate_loop_exit_test (loop_start)
reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
}
}
loop_pre_header_label = gen_label_rtx ();
/* Now copy each insn. */
for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
@ -475,9 +477,14 @@ duplicate_loop_exit_test (loop_start)
/* The jump_insn after loop_start should be followed
by barrier and loopback label. */
if (prev_nonnote_insn (label)
&& (PREV_INSN (prev_nonnote_insn (label))
== NEXT_INSN (loop_start)))
predict_insn_def (copy, PRED_LOOP_HEADER, TAKEN);
&& (prev_nonnote_insn (prev_nonnote_insn (label))
== next_nonnote_insn (loop_start)))
{
predict_insn_def (copy, PRED_LOOP_HEADER, TAKEN);
/* To keep pre-header, we need to redirect all loop
entrances before the LOOP_BEG note. */
redirect_jump (copy, loop_pre_header_label, 0);
}
else
predict_insn_def (copy, PRED_LOOP_HEADER, NOT_TAKEN);
}
@ -512,6 +519,8 @@ duplicate_loop_exit_test (loop_start)
emit_barrier_before (loop_start);
}
emit_label_before (loop_pre_header_label, loop_start);
/* Now scan from the first insn we copied to the last insn we copied
(copy) for new pseudo registers. Do this after the code to jump to
the end label since that might create a new pseudo too. */