+2011-05-02 Ulrich Weigand <ulrich.weigand@linaro.org>
+
+ PR middle-end/43085
+ Backport from mainline:
+
+ 2010-04-29 Bernd Schmidt <bernds@codesourcery.com>
+
+ From Dominique d'Humieres <dominiq@lps.ens.fr>
+ PR bootstrap/43858
+ * ifcvt.c (dead_or_predicable): Use df_simulate_find_defs to compute
+ test_set.
+
+ 2010-04-26 Bernd Schmidt <bernds@codesourcery.com>
+
+ * df-problems.c (df_simulate_initialize_forwards): Set, don't clear,
+ bits for artificial defs at the top of the block.
+ * fwprop.c (single_def_use_enter_block): Don't call it.
+
+ 2010-04-22 Bernd Schmidt <bernds@codesourcery.com>
+
+ * ifcvt.c (dead_or_predicable): Use df_simulate_find_defs and
+ df_simulate_find_noclobber_defs as appropriate. Keep track of an
+ extra set merge_set_noclobber, and use it to relax the final test
+ slightly.
+ * df.h (df_simulate_find_noclobber_defs): Declare.
+ * df-problems.c (df_simulate_find_defs): Don't ignore partial or
+ conditional defs.
+ (df_simulate_find_noclobber_defs): New function.
+
2011-04-29 John David Anglin <dave.anglin@nrc-cnrc.gc.ca>
PR target/48288
for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
{
df_ref def = *def_rec;
- /* If the def is to only part of the reg, it does
- not kill the other defs that reach here. */
- if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
+ bitmap_set_bit (defs, DF_REF_REGNO (def));
+ }
+}
+
+/* Find the set of real DEFs, which are not clobbers, for INSN. */
+
+void
+df_simulate_find_noclobber_defs (rtx insn, bitmap defs)
+{
+ df_ref *def_rec;
+ unsigned int uid = INSN_UID (insn);
+
+ for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+ {
+ df_ref def = *def_rec;
+ if (!(DF_REF_FLAGS (def) & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))
bitmap_set_bit (defs, DF_REF_REGNO (def));
}
}
the block, starting with the first one.
----------------------------------------------------------------------------*/
-/* Apply the artificial uses and defs at the top of BB in a forwards
- direction. ??? This is wrong; defs mark the point where a pseudo
- becomes live when scanning forwards (unless a def is unused). Since
- there are no REG_UNUSED notes for artificial defs, passes that
- require artificial defs probably should not call this function
- unless (as is the case for fwprop) they are correct when liveness
- bitmaps are *under*estimated. */
+/* Initialize the LIVE bitmap, which should be copied from DF_LIVE_IN or
+ DF_LR_IN for basic block BB, for forward scanning by marking artificial
+ defs live. */
void
df_simulate_initialize_forwards (basic_block bb, bitmap live)
{
df_ref def = *def_rec;
if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
- bitmap_clear_bit (live, DF_REF_REGNO (def));
+ bitmap_set_bit (live, DF_REF_REGNO (def));
}
}
while here the scan is performed forwards! So, first assume that the
def is live, and if this is not true REG_UNUSED notes will rectify the
situation. */
- df_simulate_find_defs (insn, live);
+ df_simulate_find_noclobber_defs (insn, live);
/* Clear all of the registers that go dead. */
for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
extern void df_md_add_problem (void);
extern void df_md_simulate_artificial_defs_at_top (basic_block, bitmap);
extern void df_md_simulate_one_insn (basic_block, rtx, bitmap);
+extern void df_simulate_find_noclobber_defs (rtx, bitmap);
extern void df_simulate_find_defs (rtx, bitmap);
extern void df_simulate_defs (rtx, bitmap);
extern void df_simulate_uses (rtx, bitmap);
process_uses (df_get_artificial_uses (bb_index), DF_REF_AT_TOP);
process_defs (df_get_artificial_defs (bb_index), DF_REF_AT_TOP);
- df_simulate_initialize_forwards (bb, local_lr);
+
+ /* We don't call df_simulate_initialize_forwards, as it may overestimate
+ the live registers if there are unused artificial defs. We prefer
+ liveness to be underestimated. */
FOR_BB_INSNS (bb, insn)
if (INSN_P (insn))
basic_block other_bb, basic_block new_dest, int reversep)
{
rtx head, end, jump, earliest = NULL_RTX, old_dest, new_label = NULL_RTX;
- bitmap merge_set = NULL;
+ bitmap merge_set = NULL, merge_set_noclobber = NULL;
/* Number of pending changes. */
int n_validated_changes = 0;
/* Collect:
MERGE_SET = set of registers set in MERGE_BB
+ MERGE_SET_NOCLOBBER = like MERGE_SET, but only includes registers
+ that are really set, not just clobbered.
TEST_LIVE = set of registers live at EARLIEST
- TEST_SET = set of registers set between EARLIEST and the
- end of the block. */
+ TEST_SET = set of registers set between EARLIEST and the
+ end of the block. */
merge_set = BITMAP_ALLOC (®_obstack);
+ merge_set_noclobber = BITMAP_ALLOC (®_obstack);
/* If we allocated new pseudos (e.g. in the conditional move
expander called from noce_emit_cmove), we must resize the
{
if (NONDEBUG_INSN_P (insn))
{
- unsigned int uid = INSN_UID (insn);
- df_ref *def_rec;
- for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
- {
- df_ref def = *def_rec;
- bitmap_set_bit (merge_set, DF_REF_REGNO (def));
- }
+ df_simulate_find_defs (insn, merge_set);
+ df_simulate_find_noclobber_defs (insn, merge_set_noclobber);
}
}
unsigned i;
bitmap_iterator bi;
- EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi)
+ EXECUTE_IF_SET_IN_BITMAP (merge_set_noclobber, 0, i, bi)
{
if (i < FIRST_PSEUDO_REGISTER
&& ! fixed_regs[i]
}
/* We can perform the transformation if
- MERGE_SET & (TEST_SET | TEST_LIVE)
+ MERGE_SET_NOCLOBBER & TEST_SET
+ and
+ MERGE_SET & TEST_LIVE
and
TEST_SET & DF_LIVE_IN (merge_bb)
are empty. */
- if (bitmap_intersect_p (merge_set, test_set)
+ if (bitmap_intersect_p (merge_set_noclobber, test_set)
|| bitmap_intersect_p (merge_set, test_live)
|| bitmap_intersect_p (test_set, df_get_live_in (merge_bb)))
intersect = true;
unsigned i;
bitmap_iterator bi;
- EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi)
+ EXECUTE_IF_SET_IN_BITMAP (merge_set_noclobber, 0, i, bi)
remove_reg_equal_equiv_notes_for_regno (i);
BITMAP_FREE (merge_set);
+ BITMAP_FREE (merge_set_noclobber);
}
reorder_insns (head, end, PREV_INSN (earliest));
cancel_changes (0);
fail:
if (merge_set)
- BITMAP_FREE (merge_set);
+ {
+ BITMAP_FREE (merge_set);
+ BITMAP_FREE (merge_set_noclobber);
+ }
return FALSE;
}
\f
projects / thirdparty / gcc.git / commitdiff
