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[PR45354] sel-sched: don't make EDGE_CROSSING edges fallthrough
- From: Alexander Monakov <amonakov at ispras dot ru>
- To: gcc-patches at gcc dot gnu dot org
- Cc: "Vladimir N. Makarov" <vmakarov at redhat dot com>
- Date: Tue, 30 Nov 2010 16:31:21 +0300 (MSK)
- Subject: [PR45354] sel-sched: don't make EDGE_CROSSING edges fallthrough
Hi,
We should not delete jumps if they cross hot/cold partition boundaries. The
patch adds the corresponding check in bb_has_removable_jump_to_p (which is
renamed from jump_leads_only_to_bb_p, making the name a bit closer to the
purpose).
Bootstrapped and regtested on ia64-linux, x86_64-linux. OK for trunk?
2010-11-30 Alexander Monakov <amonakov@ispras.ru>
PR rtl-optimization/45354
* sel-sched-ir.c (jump_leads_only_to_bb_p): Rename to ...
(bb_has_removable_jump_to_p): This. Update all callers. Make static.
Allow BBs ending with a conditional jump. Forbid EDGE_CROSSING jumps.
* sel-sched-ir.h (jump_leads_only_to_bb_p): Delete prototype.
testsuite:
* gcc.dg/tree-prof/pr45354.c: New.
diff --git a/gcc/sel-sched-ir.c b/gcc/sel-sched-ir.c
index 7956cd8..f7099fa 100644
--- a/gcc/sel-sched-ir.c
+++ b/gcc/sel-sched-ir.c
@@ -156,6 +156,7 @@ static void move_bb_info (basic_block, basic_block);
static void remove_empty_bb (basic_block, bool);
static void sel_merge_blocks (basic_block, basic_block);
static void sel_remove_loop_preheader (void);
+static bool bb_has_removable_jump_to_p (basic_block, basic_block);
static bool insn_is_the_only_one_in_bb_p (insn_t);
static void create_initial_data_sets (basic_block);
@@ -3675,7 +3676,7 @@ tidy_control_flow (basic_block xbb, bool full_tidying)
return changed;
/* Check if there is a unnecessary jump after insn left. */
- if (jump_leads_only_to_bb_p (BB_END (xbb), xbb->next_bb)
+ if (bb_has_removable_jump_to_p (xbb, xbb->next_bb)
&& INSN_SCHED_TIMES (BB_END (xbb)) == 0
&& !IN_CURRENT_FENCE_P (BB_END (xbb)))
{
@@ -3716,7 +3717,7 @@ tidy_control_flow (basic_block xbb, bool full_tidying)
/* And unconditional jump in previous basic block leads to
next basic block of XBB and this jump can be safely removed. */
&& in_current_region_p (xbb->prev_bb)
- && jump_leads_only_to_bb_p (BB_END (xbb->prev_bb), xbb->next_bb)
+ && bb_has_removable_jump_to_p (xbb->prev_bb, xbb->next_bb)
&& INSN_SCHED_TIMES (BB_END (xbb->prev_bb)) == 0
/* Also this jump is not at the scheduling boundary. */
&& !IN_CURRENT_FENCE_P (BB_END (xbb->prev_bb)))
@@ -6104,22 +6105,19 @@ sel_is_loop_preheader_p (basic_block bb)
return false;
}
-/* Checks whether JUMP leads to basic block DEST_BB and no other blocks. */
-bool
-jump_leads_only_to_bb_p (insn_t jump, basic_block dest_bb)
+/* Check whether JUMP_BB ends with a jump insn that leads only to DEST_BB and
+ can be removed, making the corresponding edge fallthrough (assuming that
+ all basic blocks between JUMP_BB and DEST_BB are empty). */
+static bool
+bb_has_removable_jump_to_p (basic_block jump_bb, basic_block dest_bb)
{
- basic_block jump_bb = BLOCK_FOR_INSN (jump);
-
- /* It is not jump, jump with side-effects or jump can lead to several
- basic blocks. */
- if (!onlyjump_p (jump)
- || !any_uncondjump_p (jump))
+ if (!onlyjump_p (BB_END (jump_bb)))
return false;
/* Several outgoing edges, abnormal edge or destination of jump is
not DEST_BB. */
if (EDGE_COUNT (jump_bb->succs) != 1
- || EDGE_SUCC (jump_bb, 0)->flags & EDGE_ABNORMAL
+ || EDGE_SUCC (jump_bb, 0)->flags & (EDGE_ABNORMAL | EDGE_CROSSING)
|| EDGE_SUCC (jump_bb, 0)->dest != dest_bb)
return false;
@@ -6199,7 +6197,7 @@ sel_remove_loop_preheader (void)
basic block if it becomes empty. */
if (next_bb->prev_bb == prev_bb
&& prev_bb != ENTRY_BLOCK_PTR
- && jump_leads_only_to_bb_p (BB_END (prev_bb), next_bb))
+ && bb_has_removable_jump_to_p (prev_bb, next_bb))
{
redirect_edge_and_branch (EDGE_SUCC (prev_bb, 0), next_bb);
if (BB_END (prev_bb) == bb_note (prev_bb))
diff --git a/gcc/sel-sched-ir.h b/gcc/sel-sched-ir.h
index 9ab0466..1f3dec4 100644
--- a/gcc/sel-sched-ir.h
+++ b/gcc/sel-sched-ir.h
@@ -1590,7 +1590,6 @@ extern bool sel_remove_insn (insn_t, bool, bool);
extern bool bb_header_p (insn_t);
extern void sel_init_invalid_data_sets (insn_t);
extern bool insn_at_boundary_p (insn_t);
-extern bool jump_leads_only_to_bb_p (insn_t, basic_block);
/* Basic block and CFG functions. */
diff --git a/gcc/testsuite/gcc.dg/tree-prof/pr45354.c b/gcc/testsuite/gcc.dg/tree-prof/pr45354.c
index e69de29..b30ad77 100644
--- a/gcc/testsuite/gcc.dg/tree-prof/pr45354.c
+++ b/gcc/testsuite/gcc.dg/tree-prof/pr45354.c
@@ -0,0 +1,43 @@
+/* { dg-require-effective-target freorder } */
+/* { dg-options "-O -freorder-blocks-and-partition -fschedule-insns -fselective-scheduling" { target powerpc*-*-* ia64-*-* x86_64-*-* } } */
+
+extern void abort (void);
+
+int ifelse_val2;
+
+int __attribute__((noinline))
+test_ifelse2 (int i)
+{
+ int result = 0;
+ if (!i) /* count(6) */
+ result = 1; /* count(1) */
+ if (i == 1) /* count(6) */
+ result = 1024;
+ if (i == 2) /* count(6) */
+ result = 2; /* count(3) */
+ if (i == 3) /* count(6) */
+ return 8; /* count(2) */
+ if (i == 4) /* count(4) */
+ return 2048;
+ return result; /* count(4) */
+}
+
+void __attribute__((noinline))
+call_ifelse ()
+{
+ ifelse_val2 += test_ifelse2 (0);
+ ifelse_val2 += test_ifelse2 (2);
+ ifelse_val2 += test_ifelse2 (2);
+ ifelse_val2 += test_ifelse2 (2);
+ ifelse_val2 += test_ifelse2 (3);
+ ifelse_val2 += test_ifelse2 (3);
+}
+
+int
+main()
+{
+ call_ifelse ();
+ if (ifelse_val2 != 23)
+ abort ();
+ return 0;
+}