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flow.c (compute_flow_dominators): No longer treat basic block 0 or (n_basic_blocks - 1) specially.

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* flow.c (compute_flow_dominators): No longer treat basic block 0
        or (n_basic_blocks - 1) specially.  Clear the AUX field before
        starting computation of doms/pdoms.  Fix initial state for pdoms.

From-SVN: r30467
This commit is contained in:
Jeffrey A Law 1999-11-10 07:05:42 +00:00 committed by Jeff Law
parent ca76ec07e4
commit 973d12cb61
2 changed files with 83 additions and 12 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
Wed Nov 10 00:02:53 1999 Jeffrey A Law (law@cygnus.com)
* flow.c (compute_flow_dominators): No longer treat basic block 0
or (n_basic_blocks - 1) specially. Clear the AUX field before
starting computation of doms/pdoms. Fix initial state for pdoms.
Wed Nov 10 03:58:08 1999 Alexandre Oliva <oliva@lsd.ic.unicamp.br>
* Makefile.in ($(HOST_PREFIX_1)rtl.o): Update dependencies to

89
gcc/flow.c
View File

@ -5339,15 +5339,23 @@ compute_flow_dominators (dominators, post_dominators)
if (dominators)
{
/* Clear the AUX field for each basic block. */
for (bb = 0; bb < n_basic_blocks; bb++)
BASIC_BLOCK (bb)->aux = NULL;
/* We want a maximal solution, so initially assume everything dominates
everything else. */
sbitmap_vector_ones (dominators, n_basic_blocks);
sbitmap_zero (dominators[0]);
SET_BIT (dominators[0], 0);
/* Put the successors of the entry block on the worklist. */
for (e = BASIC_BLOCK (0)->succ; e; e = e->succ_next)
for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
{
*tos++ = e->dest;
e->dest->aux = e;
/* We use the block's aux field to track blocks which are in
the worklist; we also use it to quickly determine which blocks
are successors of the ENTRY block. */
e->dest->aux = ENTRY_BLOCK_PTR;
}
/* Iterate until the worklist is empty. */
@ -5355,10 +5363,34 @@ compute_flow_dominators (dominators, post_dominators)
{
/* Take the first entry off the worklist. */
basic_block b = *--tos;
b->aux = NULL;
bb = b->index;
sbitmap_intersection_of_preds (temp_bitmap[bb], dominators, bb);
/* Compute the intersection of the dominators of all the
predecessor blocks.
If one of the predecessor blocks is the ENTRY block, then the
intersection of the dominators of the predecessor blocks is
defined as the null set. We can identify such blocks by the
special value in the AUX field in the block structure. */
if (b->aux == ENTRY_BLOCK_PTR)
{
/* Do not clear the aux field for blocks which are
successors of the ENTRY block. That way we we never
add them to the worklist again.
The intersect of dominators of the preds of this block is
defined as the null set. */
sbitmap_zero (temp_bitmap[bb]);
}
else
{
/* Clear the aux field of this block so it can be added to
the worklist again if necessary. */
b->aux = NULL;
sbitmap_intersection_of_preds (temp_bitmap[bb], dominators, bb);
}
/* Make sure each block always dominates itself. */
SET_BIT (temp_bitmap[bb], bb);
/* If the out state of this block changed, then we need to
@ -5380,15 +5412,23 @@ compute_flow_dominators (dominators, post_dominators)
if (post_dominators)
{
/* Clear the AUX field for each basic block. */
for (bb = 0; bb < n_basic_blocks; bb++)
BASIC_BLOCK (bb)->aux = NULL;
/* We want a maximal solution, so initially assume everything post
dominates everything else. */
sbitmap_vector_ones (post_dominators, n_basic_blocks);
sbitmap_zero (post_dominators[n_basic_blocks - 1]);
SET_BIT (post_dominators[n_basic_blocks - 1], 0);
/* Put the predecessors of the exit block on the worklist. */
for (e = BASIC_BLOCK (n_basic_blocks - 1)->pred; e; e = e->pred_next)
for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next)
{
*tos++ = e->src;
e->src->aux = e;
/* We use the block's aux field to track blocks which are in
the worklist; we also use it to quickly determine which blocks
are predecessors of the EXIT block. */
e->src->aux = EXIT_BLOCK_PTR;
}
/* Iterate until the worklist is empty. */
@ -5396,10 +5436,35 @@ compute_flow_dominators (dominators, post_dominators)
{
/* Take the first entry off the worklist. */
basic_block b = *--tos;
b->aux = NULL;
bb = b->index;
sbitmap_intersection_of_succs (temp_bitmap[bb], post_dominators, bb);
/* Compute the intersection of the post dominators of all the
successor blocks.
If one of the successor blocks is the EXIT block, then the
intersection of the dominators of the successor blocks is
defined as the null set. We can identify such blocks by the
special value in the AUX field in the block structure. */
if (b->aux == EXIT_BLOCK_PTR)
{
/* Do not clear the aux field for blocks which are
predecessors of the EXIT block. That way we we never
add them to the worklist again.
The intersect of dominators of the succs of this block is
defined as the null set. */
sbitmap_zero (temp_bitmap[bb]);
}
else
{
/* Clear the aux field of this block so it can be added to
the worklist again if necessary. */
b->aux = NULL;
sbitmap_intersection_of_succs (temp_bitmap[bb],
post_dominators, bb);
}
/* Make sure each block always post dominates itself. */
SET_BIT (temp_bitmap[bb], bb);
/* If the out state of this block changed, then we need to