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stmt.c (expand_end_loop): Tidy.

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* stmt.c (expand_end_loop): Tidy.  Allow unconditional
        jumps out of the loop to be treated as part of the exit test.

From-SVN: r21782
This commit is contained in:
Mark Mitchell 1998-08-17 09:30:15 +00:00 • committed by Jeff Law
parent 804a4e13f8
commit 0720f6fbcd
2 changed files with 51 additions and 33 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
Mon Aug 17 10:28:52 1998 Mark Mitchell <mark@markmitchell.com>
* stmt.c (expand_end_loop): Tidy. Allow unconditional
jumps out of the loop to be treated as part of the exit test.
Mon Aug 17 10:06:11 1998 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
Jeff Law <law@cygnus.com>

79
gcc/stmt.c
View file

@ -1911,13 +1911,8 @@ expand_loop_continue_here ()
void
expand_end_loop ()
{
register rtx insn;
register rtx start_label;
rtx last_test_insn = 0;
int num_insns = 0;
insn = get_last_insn ();
start_label = loop_stack->data.loop.start_label;
rtx start_label = loop_stack->data.loop.start_label;
rtx insn = get_last_insn ();
/* Mark the continue-point at the top of the loop if none elsewhere. */
if (start_label == loop_stack->data.loop.continue_label)
@ -1938,7 +1933,7 @@ expand_end_loop ()
if (test) goto end_label;
body;
goto start_label;
end_label;
end_label:
transform it to look like:
@ -1948,10 +1943,11 @@ expand_end_loop ()
start_label:
if (test) goto end_label;
goto newstart_label;
end_label;
end_label:
Here, the `test' may actually consist of some reasonably complex
code, terminating in a test. */
if (optimize
&&
! (GET_CODE (insn) == JUMP_INSN
@ -1960,6 +1956,8 @@ expand_end_loop ()
&& GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE))
{
int eh_regions = 0;
int num_insns = 0;
rtx last_test_insn = NULL_RTX;
/* Scan insns from the top of the loop looking for a qualified
conditional exit. */
@ -2036,31 +2034,46 @@ expand_end_loop ()
So we don't look for tests within an EH region. */
continue;
if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == SET
&& SET_DEST (PATTERN (insn)) == pc_rtx
&& GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE
&& ((GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == LABEL_REF
&& ((XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
== loop_stack->data.loop.end_label)
|| (XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
== loop_stack->data.loop.alt_end_label)))
|| (GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 2)) == LABEL_REF
&& ((XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
== loop_stack->data.loop.end_label)
|| (XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
== loop_stack->data.loop.alt_end_label)))))
last_test_insn = insn;
if (last_test_insn == 0 && GET_CODE (insn) == JUMP_INSN
if (GET_CODE (insn) == JUMP_INSN
&& GET_CODE (PATTERN (insn)) == SET
&& SET_DEST (PATTERN (insn)) == pc_rtx
&& GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF
&& ((XEXP (SET_SRC (PATTERN (insn)), 0)
== loop_stack->data.loop.end_label)
|| (XEXP (SET_SRC (PATTERN (insn)), 0)
== loop_stack->data.loop.alt_end_label)))
/* Include BARRIER. */
last_test_insn = NEXT_INSN (insn);
&& SET_DEST (PATTERN (insn)) == pc_rtx)
{
/* This is indeed a jump. */
rtx dest1 = NULL_RTX;
rtx dest2 = NULL_RTX;
rtx potential_last_test;
if (GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE)
{
/* A conditional jump. */
dest1 = XEXP (SET_SRC (PATTERN (insn)), 1);
dest2 = XEXP (SET_SRC (PATTERN (insn)), 2);
potential_last_test = insn;
}
else
{
/* An unconditional jump. */
dest1 = SET_SRC (PATTERN (insn));
/* Include the BARRIER after the JUMP. */
potential_last_test = NEXT_INSN (insn);
}
do {
if (dest1 && GET_CODE (dest1) == LABEL_REF
&& ((XEXP (dest1, 0)
== loop_stack->data.loop.alt_end_label)
|| (XEXP (dest1, 0)
== loop_stack->data.loop.end_label)))
{
last_test_insn = potential_last_test;
break;
}
/* If this was a conditional jump, there may be
another label at which we should look. */
dest1 = dest2;
dest2 = NULL_RTX;
} while (dest1);
}
}
if (last_test_insn != 0 && last_test_insn != get_last_insn ())