Fix for GCSE and abnormal edges
Richard Henderson
rth@redhat.com
Wed Dec 6 10:46:00 GMT 2000
On Wed, Dec 06, 2000 at 11:27:20AM +0100, Michael Matz wrote:
> * gcse.c (compute_pre_data): New locals abnormal_dests, trapping_expr.
> Use them to kill trapping expressions in destination blocks of
> abnormal edges.
Thanks.
I don't see the point of computing a bitmap for abnormal_dests
as opposed to just computing what we need when it is needed.
So I've tweeked the patch as follows. Committed.
r~
Index: gcse.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/gcse.c,v
retrieving revision 1.111
diff -c -p -d -r1.111 gcse.c
*** gcse.c 2000/11/21 21:00:20 1.111
--- gcse.c 2000/12/06 18:41:54
*************** free_pre_mem ()
*** 4157,4167 ****
--- 4157,4180 ----
static void
compute_pre_data ()
{
+ sbitmap trapping_expr;
int i;
+ unsigned int ui;
compute_local_properties (transp, comp, antloc, 0);
sbitmap_vector_zero (ae_kill, n_basic_blocks);
+ /* Collect expressions which might trap. */
+ trapping_expr = sbitmap_alloc (n_exprs);
+ sbitmap_zero (trapping_expr);
+ for (ui = 0; ui < expr_hash_table_size; ui++)
+ {
+ struct expr *e;
+ for (e = expr_hash_table[ui]; e != NULL; e = e->next_same_hash)
+ if (may_trap_p (e->expr))
+ SET_BIT (trapping_expr, e->bitmap_index);
+ }
+
/* Compute ae_kill for each basic block using:
~(TRANSP | COMP)
*************** compute_pre_data ()
*** 4170,4175 ****
--- 4183,4202 ----
for (i = 0; i < n_basic_blocks; i++)
{
+ edge e;
+
+ /* If the current block is the destination of an abnormal edge, we
+ kill all trapping expressions because we won't be able to properly
+ place the instruction on the edge. So make them neither
+ anticipatable nor transparent. This is fairly conservative. */
+ for (e = BASIC_BLOCK (i)->pred; e ; e = e->pred_next)
+ if (e->flags & EDGE_ABNORMAL)
+ {
+ sbitmap_difference (antloc[i], antloc[i], trapping_expr);
+ sbitmap_difference (transp[i], transp[i], trapping_expr);
+ break;
+ }
+
sbitmap_a_or_b (ae_kill[i], transp[i], comp[i]);
sbitmap_not (ae_kill[i], ae_kill[i]);
}
*************** compute_pre_data ()
*** 4180,4185 ****
--- 4207,4213 ----
antloc = NULL;
free (ae_kill);
ae_kill = NULL;
+ free (trapping_expr);
}
/* PRE utilities */
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