Doing the indirect jump optimization turned out to be quite easy.
Bootstrapped and regression tested powerpc64le-linux, gcc-6, gcc-5 and
gcc-4.9. Bootstrap and regression test x86_64-linux still running.
OK to apply?
gcc/
PR rtl-optimization/69195
PR rtl-optimization/47992
* ira.c (recorded_label_ref): Delete.
(update_equiv_regs): Return void.
(indirect_jump_optimize): New function.
(ira): Call indirect_jump_optimize and delete_trivially_dead_insns
before regstat_compute_ri. Don't rebuild_jump_labels here.
Delete update_regstat.
gcc/testsuite/
* gcc.dg/pr69195.c: New.
* gcc.dg/pr69238.c: New.
diff --git a/gcc/ira.c b/gcc/ira.c
index 0973258..5e7a2ed 100644
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -3319,9 +3319,6 @@ adjust_cleared_regs (rtx loc, const_rtx old_rtx
ATTRIBUTE_UNUSED, void *data)
return NULL_RTX;
}
-/* Nonzero if we recorded an equivalence for a LABEL_REF. */
-static int recorded_label_ref;
-
/* Find registers that are equivalent to a single value throughout the
compilation (either because they can be referenced in memory or are
set once from a single constant). Lower their priority for a
@@ -3331,10 +3328,8 @@ static int recorded_label_ref;
value into the using insn. If it succeeds, we can eliminate the
register completely.
- Initialize init_insns in ira_reg_equiv array.
-
- Return non-zero if jump label rebuilding should be done. */
-static int
+ Initialize init_insns in ira_reg_equiv array. */
+static void
update_equiv_regs (void)
{
rtx_insn *insn;
@@ -3343,10 +3338,6 @@ update_equiv_regs (void)
bitmap cleared_regs;
bool *pdx_subregs;
- /* We need to keep track of whether or not we recorded a LABEL_REF so
- that we know if the jump optimizer needs to be rerun. */
- recorded_label_ref = 0;
-
/* Use pdx_subregs to show whether a reg is used in a paradoxical
subreg. */
pdx_subregs = XCNEWVEC (bool, max_regno);
@@ -3578,17 +3569,6 @@ update_equiv_regs (void)
= gen_rtx_INSN_LIST (VOIDmode, insn,
ira_reg_equiv[regno].init_insns);
- /* Record whether or not we created a REG_EQUIV note for a
LABEL_REF.
- We might end up substituting the LABEL_REF for uses of the
- pseudo here or later. That kind of transformation may turn an
- indirect jump into a direct jump, in which case we must rerun
the
- jump optimizer to ensure that the JUMP_LABEL fields are valid.
*/
- if (GET_CODE (x) == LABEL_REF
- || (GET_CODE (x) == CONST
- && GET_CODE (XEXP (x, 0)) == PLUS
- && (GET_CODE (XEXP (XEXP (x, 0), 0)) == LABEL_REF)))
- recorded_label_ref = 1;
-
reg_equiv[regno].replacement = x;
reg_equiv[regno].src_p = &SET_SRC (set);
reg_equiv[regno].loop_depth = (short) loop_depth;
@@ -3706,9 +3686,9 @@ update_equiv_regs (void)
if (! INSN_P (insn))
continue;
- /* Don't substitute into a non-local goto, this confuses CFG. */
- if (JUMP_P (insn)
- && find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
+ /* Don't substitute into jumps. indirect_jump_optimize does
+ this for anything we are prepared to handle. */
+ if (JUMP_P (insn))
continue;
for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
@@ -3860,11 +3840,50 @@ update_equiv_regs (void)
end_alias_analysis ();
free (reg_equiv);
free (pdx_subregs);
- return recorded_label_ref;
}
-
+/* A pass over indirect jumps, converting simple cases to direct jumps. */
+static void
+indirect_jump_optimize (void)
+{
+ basic_block bb;
+ bool rebuild_p = false;
+ FOR_EACH_BB_REVERSE_FN (bb, cfun)
+ {
+ rtx_insn *insn = BB_END (bb);
+ if (!JUMP_P (insn))
+ continue;
+
+ rtx x = pc_set (insn);
+ if (!x || !REG_P (SET_SRC (x)))
+ continue;
+
+ int regno = REGNO (SET_SRC (x));
+ if (DF_REG_DEF_COUNT (regno) == 1)
+ {
+ rtx_insn *def_insn = DF_REF_INSN (DF_REG_DEF_CHAIN (regno));
+ rtx note = find_reg_note (def_insn, REG_LABEL_OPERAND, NULL_RTX);
+
+ if (note)
+ {
+ rtx lab = gen_rtx_LABEL_REF (Pmode, XEXP (note, 0));
+ if (validate_replace_rtx (SET_SRC (x), lab, insn))
+ rebuild_p = true;
+ }
+ }
+ }
+
+ if (rebuild_p)
+ {
+ timevar_push (TV_JUMP);
+ rebuild_jump_labels (get_insns ());
+ if (purge_all_dead_edges ())
+ delete_unreachable_blocks ();
+ timevar_pop (TV_JUMP);
+ }
+}
+
/* Set up fields memory, constant, and invariant from init_insns in
the structures of array ira_reg_equiv. */
static void
@@ -5090,7 +5109,6 @@ ira (FILE *f)
{
bool loops_p;
int ira_max_point_before_emit;
- int rebuild_p;
bool saved_flag_caller_saves = flag_caller_saves;
enum ira_region saved_flag_ira_region = flag_ira_region;
@@ -5167,6 +5185,10 @@ ira (FILE *f)
df_clear_flags (DF_NO_INSN_RESCAN);
+ indirect_jump_optimize ();
+ if (delete_trivially_dead_insns (get_insns (), max_reg_num ()))
+ df_analyze ();
+
regstat_init_n_sets_and_refs ();
regstat_compute_ri ();
@@ -5184,32 +5206,12 @@ ira (FILE *f)
if (resize_reg_info () && flag_ira_loop_pressure)
ira_set_pseudo_classes (true, ira_dump_file);
- rebuild_p = update_equiv_regs ();
+ update_equiv_regs ();
setup_reg_equiv ();
setup_reg_equiv_init ();
- bool update_regstat = false;
-
- if (optimize && rebuild_p)
- {
- timevar_push (TV_JUMP);
- rebuild_jump_labels (get_insns ());
- if (purge_all_dead_edges ())
- {
- delete_unreachable_blocks ();
- update_regstat = true;
- }
- timevar_pop (TV_JUMP);
- }
-
allocated_reg_info_size = max_reg_num ();
- if (delete_trivially_dead_insns (get_insns (), max_reg_num ()))
- {
- df_analyze ();
- update_regstat = true;
- }
-
/* It is not worth to do such improvement when we use a simple
allocation because of -O0 usage or because the function is too
big. */
@@ -5319,7 +5321,7 @@ ira (FILE *f)
check_allocation ();
#endif
- if (update_regstat || max_regno != max_regno_before_ira)
+ if (max_regno != max_regno_before_ira)
{
regstat_free_n_sets_and_refs ();
regstat_free_ri ();
diff --git a/gcc/testsuite/gcc.dg/pr69195.c b/gcc/testsuite/gcc.dg/pr69195.c
new file mode 100644
index 0000000..af373a1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr69195.c
@@ -0,0 +1,27 @@
+/* { dg-do run } */
+/* { dg-options "-O3 -fno-dce -fno-forward-propagate" } */
+
+void __attribute__ ((noinline, noclone))
+foo (int *a, int n)
+{
+ int *lasta = a + n;
+ for (; a != lasta; a++)
+ {
+ *a *= 2;
+ a[1] = a[-1] + a[-2];
+ }
+}
+
+int
+main ()
+{
+ int a[16] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
+ int r[16] = { 1, 2, 6, 6, 16, 24, 44, 80,
+ 136, 248, 432, 768, 1360, 2400, 4256, 3760 };
+ unsigned i;
+ foo (&a[2], 13);
+ for (i = 0; i < 8; ++i)
+ if (a[i] != r[i])
+ __builtin_abort ();
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr69238.c b/gcc/testsuite/gcc.dg/pr69238.c
new file mode 100644
index 0000000..3538e63
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr69238.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fno-dce -fno-forward-propagate -fno-rerun-cse-after-loop
-funroll-loops" } */
+
+
+#define N 32
+
+short sa[N];
+short sb[N];
+int ia[N];
+int ib[N];
+
+int __attribute__ ((noinline, noclone))
+main1 (int n)
+{
+ int i;
+ for (i = 0; i < n; i++)
+ {
+ sa[i+7] = sb[i];
+ ia[i+3] = ib[i+1];
+ }
+ return 0;
+}
+
+int
+main (void)
+{
+ return main1 (N-7);
+}
--
Alan Modra
Australia Development Lab, IBM
