2002-06-13 Jeffrey Law <law@redhat.com>
+ * gcse.c (delete_null_pointer_checks_1): Inform caller if any
+ null pointer checks were eliminated. Update prototype.
+ (delete_null_pointer_checks): Similarly.
+ * rtl.h (delete_null_pointer_checks): Update prototype.
+ * toplev.c (rest_of_compilation): Only run cleanup_cfg if
+ delete_null_pointer_checks deletes one or more null
+ pointer checks. Do not run cleanup_cfg before gcse, the
+ CFG is accurate and optimized at that point..
+
* rs6000.c (rs6000_frame_related): Avoid unwanted sharing
of hard registers.
static int classic_gcse PARAMS ((void));
static int one_classic_gcse_pass PARAMS ((int));
static void invalidate_nonnull_info PARAMS ((rtx, rtx, void *));
-static void delete_null_pointer_checks_1 PARAMS ((unsigned int *,
+static int delete_null_pointer_checks_1 PARAMS ((unsigned int *,
sbitmap *, sbitmap *,
struct null_pointer_info *));
static rtx process_insert_insn PARAMS ((struct expr *));
NPI. NONNULL_AVIN and NONNULL_AVOUT are pre-allocated sbitmaps;
they are not our responsibility to free. */
-static void
+static int
delete_null_pointer_checks_1 (block_reg, nonnull_avin,
nonnull_avout, npi)
unsigned int *block_reg;
basic_block bb, current_block;
sbitmap *nonnull_local = npi->nonnull_local;
sbitmap *nonnull_killed = npi->nonnull_killed;
+ int something_changed = 0;
/* Compute local properties, nonnull and killed. A register will have
the nonnull property if at the end of the current block its value is
emit_barrier_after (new_jump);
}
+ something_changed = 1;
delete_insn (last_insn);
if (compare_and_branch == 2)
delete_insn (earliest);
block.) */
block_reg[bb->index] = 0;
}
+
+ return something_changed;
}
/* Find EQ/NE comparisons against zero which can be (indirectly) evaluated
This could probably be integrated with global cprop with a little work. */
-void
+int
delete_null_pointer_checks (f)
rtx f ATTRIBUTE_UNUSED;
{
int regs_per_pass;
int max_reg;
struct null_pointer_info npi;
+ int something_changed = 0;
/* If we have only a single block, then there's nothing to do. */
if (n_basic_blocks <= 1)
- return;
+ return 0;
/* Trying to perform global optimizations on flow graphs which have
a high connectivity will take a long time and is unlikely to be
a couple switch statements. So we require a relatively large number
of basic blocks and the ratio of edges to blocks to be high. */
if (n_basic_blocks > 1000 && n_edges / n_basic_blocks >= 20)
- return;
+ return 0;
/* We need four bitmaps, each with a bit for each register in each
basic block. */
{
npi.min_reg = reg;
npi.max_reg = MIN (reg + regs_per_pass, max_reg);
- delete_null_pointer_checks_1 (block_reg, nonnull_avin,
- nonnull_avout, &npi);
+ something_changed |= delete_null_pointer_checks_1 (block_reg,
+ nonnull_avin,
+ nonnull_avout,
+ &npi);
}
/* Free the table of registers compared at the end of every block. */
sbitmap_vector_free (npi.nonnull_killed);
sbitmap_vector_free (nonnull_avin);
sbitmap_vector_free (nonnull_avout);
+
+ return something_changed;
}
/* Code Hoisting variables and subroutines. */
if (rtl_dump_file)
dump_flow_info (rtl_dump_file);
- delete_null_pointer_checks (insns);
+ if (delete_null_pointer_checks (insns))
+ cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_PRE_LOOP);
- cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_PRE_LOOP);
close_dump_file (DFI_null, print_rtl_with_bb, insns);
}
if (tem || optimize > 1)
cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_PRE_LOOP);
/* Try to identify useless null pointer tests and delete them. */
- if (flag_delete_null_pointer_checks || flag_thread_jumps)
+ if (flag_delete_null_pointer_checks)
{
timevar_push (TV_JUMP);
if (flag_delete_null_pointer_checks)
- delete_null_pointer_checks (insns);
- /* CFG is no longer maintained up-to-date. */
+ if (delete_null_pointer_checks (insns))
+ cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_PRE_LOOP);
timevar_pop (TV_JUMP);
}
timevar_push (TV_GCSE);
open_dump_file (DFI_gcse, decl);
- cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_PRE_LOOP);
tem = gcse_main (insns, rtl_dump_file);
rebuild_jump_labels (insns);
delete_trivially_dead_insns (insns, max_reg_num ());