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flow.c (tidy_fallthru_edges): Split out from ...

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* flow.c (tidy_fallthru_edges): Split out from ...
        (delete_unreachable_blocks): ... here.
        (find_basic_blocks): Use it.

From-SVN: r31857
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Richard Henderson 2000-02-08 15:48:32 -08:00 committed by Richard Henderson
parent f5a500108a
commit 5568fb48cc
2 changed files with 52 additions and 34 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2000-02-08 Richard Henderson <rth@cygnus.com>
* flow.c (tidy_fallthru_edges): Split out from ...
(delete_unreachable_blocks): ... here.
(find_basic_blocks): Use it.
Tue Feb 8 15:51:50 2000 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
* stmt.c (expand_decl): Do set RTX_UNCHANGING_P for TREE_READONLY.

80
gcc/flow.c
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@ -309,7 +309,7 @@ static void merge_blocks_nomove PARAMS ((basic_block, basic_block));
static int merge_blocks PARAMS ((edge,basic_block,basic_block));
static void try_merge_blocks PARAMS ((void));
static void tidy_fallthru_edge PARAMS ((edge,basic_block,basic_block));
static void tidy_fallthru_edges PARAMS ((void));
static int verify_wide_reg_1 PARAMS ((rtx *, void *));
static void verify_wide_reg PARAMS ((int, rtx, rtx));
static void verify_local_live_at_start PARAMS ((regset, basic_block));
@ -422,6 +422,11 @@ find_basic_blocks (f, nregs, file)
/* Discover the edges of our cfg. */
record_active_eh_regions (f);
make_edges (label_value_list);
/* Do very simple cleanup now, for the benefit of code that runs between
here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
tidy_fallthru_edges ();
mark_critical_edges ();
#ifdef ENABLE_CHECKING
@ -1746,36 +1751,7 @@ delete_unreachable_blocks ()
deleted_handler |= delete_block (b);
}
/* Fix up edges that now fall through, or rather should now fall through
but previously required a jump around now deleted blocks. Simplify
the search by only examining blocks numerically adjacent, since this
is how find_basic_blocks created them. */
for (i = 1; i < n_basic_blocks; ++i)
{
basic_block b = BASIC_BLOCK (i - 1);
basic_block c = BASIC_BLOCK (i);
edge s;
/* We care about simple conditional or unconditional jumps with
a single successor.
If we had a conditional branch to the next instruction when
find_basic_blocks was called, then there will only be one
out edge for the block which ended with the conditional
branch (since we do not create duplicate edges).
Furthermore, the edge will be marked as a fallthru because we
merge the flags for the duplicate edges. So we do not want to
check that the edge is not a FALLTHRU edge. */
if ((s = b->succ) != NULL
&& s->succ_next == NULL
&& s->dest == c
/* If the jump insn has side effects, we can't tidy the edge. */
&& (GET_CODE (b->end) != JUMP_INSN
|| onlyjump_p (b->end)))
tidy_fallthru_edge (s, b, c);
}
tidy_fallthru_edges ();
/* If we deleted an exception handler, we may have EH region begin/end
blocks to remove as well. */
@ -2365,9 +2341,8 @@ try_merge_blocks ()
}
}
/* The given edge should potentially a fallthru edge. If that is in
fact true, delete the unconditional jump and barriers that are in
the way. */
/* The given edge should potentially be a fallthru edge. If that is in
fact true, delete the jump and barriers that are in the way. */
static void
tidy_fallthru_edge (e, b, c)
@ -2419,6 +2394,43 @@ tidy_fallthru_edge (e, b, c)
e->flags |= EDGE_FALLTHRU;
}
/* Fix up edges that now fall through, or rather should now fall through
but previously required a jump around now deleted blocks. Simplify
the search by only examining blocks numerically adjacent, since this
is how find_basic_blocks created them. */
static void
tidy_fallthru_edges ()
{
int i;
for (i = 1; i < n_basic_blocks; ++i)
{
basic_block b = BASIC_BLOCK (i - 1);
basic_block c = BASIC_BLOCK (i);
edge s;
/* We care about simple conditional or unconditional jumps with
a single successor.
If we had a conditional branch to the next instruction when
find_basic_blocks was called, then there will only be one
out edge for the block which ended with the conditional
branch (since we do not create duplicate edges).
Furthermore, the edge will be marked as a fallthru because we
merge the flags for the duplicate edges. So we do not want to
check that the edge is not a FALLTHRU edge. */
if ((s = b->succ) != NULL
&& s->succ_next == NULL
&& s->dest == c
/* If the jump insn has side effects, we can't tidy the edge. */
&& (GET_CODE (b->end) != JUMP_INSN
|| onlyjump_p (b->end)))
tidy_fallthru_edge (s, b, c);
}
}
/* Discover and record the loop depth at the head of each basic block. */
void