[PATCH v5 20/22] RISC-V: Return the matched macro-fusion operation

Ready-list scheduling must probe potential pairs without emitting dump
records.  Add a helper that returns the matched fusion operation and keep
dumping in TARGET_SCHED_MACRO_FUSION_PAIR_P.

gcc/ChangeLog:

	* config/riscv/riscv-fusion.cc (riscv_fusion_type_name): New
	function.
	(riscv_get_fusion_pair_type): Likewise.
	(riscv_macro_fusion_pair_p): Use riscv_get_fusion_pair_type and
	emit the matched operation.
	* config/riscv/riscv-protos.h (riscv_get_fusion_pair_type):
	Declare.

Signed-off-by: Jin Ma <[email protected]>
---
 gcc/config/riscv/riscv-fusion.cc | 55 +++++++++++++++++++++-----------
 gcc/config/riscv/riscv-protos.h  |  2 ++
 2 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/gcc/config/riscv/riscv-fusion.cc b/gcc/config/riscv/riscv-fusion.cc
index 06cdab5694d..aca5e757463 100644
--- a/gcc/config/riscv/riscv-fusion.cc
+++ b/gcc/config/riscv/riscv-fusion.cc
@@ -2028,38 +2028,57 @@ static const struct riscv_fusion_entry riscv_fusion_table[] =
     riscv_fuse_logic_logic, "RISCV_FUSE_LOGIC_LOGIC" },
 };
 
-/* Implement TARGET_SCHED_MACRO_FUSION_PAIR_P.  Return true if PREV and CURR
-   should be kept together during scheduling.  */
+/* Return the name of fusion operation OP.  */
 
-bool
-riscv_macro_fusion_pair_p (rtx_insn *prev, rtx_insn *curr)
+static const char *
+riscv_fusion_type_name (enum riscv_fusion_pairs op)
+{
+  for (size_t i = 0; i < ARRAY_SIZE (riscv_fusion_table); i++)
+    if (riscv_fusion_table[i].op == op)
+      return riscv_fusion_table[i].fusion_type;
+
+  gcc_unreachable ();
+}
+
+/* Return the enabled fusion operation matched by PREV and CURR, or
+   RISCV_FUSE_NOTHING if the instructions do not form a fusion pair.  */
+
+enum riscv_fusion_pairs
+riscv_get_fusion_pair_type (rtx_insn *prev, rtx_insn *curr)
 {
-  /* If fusion is not enabled, then there's nothing to do.  */
   if (!riscv_macro_fusion_p ())
-    return false;
+    return RISCV_FUSE_NOTHING;
 
-  /* If PREV is already marked as fused, then we can't fuse CURR with PREV
-     and if we were to fuse them we'd end up with a blob of insns that
-     essentially are an atomic unit which is bad for scheduling.  */
+  /* Do not extend an existing fusion group.  */
   if (SCHED_GROUP_P (prev))
-    return false;
+    return RISCV_FUSE_NOTHING;
 
   for (size_t i = 0; i < ARRAY_SIZE (riscv_fusion_table); i++)
     {
       const struct riscv_fusion_entry *entry = &riscv_fusion_table[i];
 
-      /* Check if this fusion type is enabled.  */
       if (!riscv_fusion_enabled_p (entry->op))
 	continue;
 
       if (entry->checker (prev, curr))
-	{
-	  if (dump_file)
-	    fprintf (dump_file, ";; macro fusion: insn %d + insn %d -> %s\n",
-		     INSN_UID (prev), INSN_UID (curr), entry->fusion_type);
-	  return true;
-	}
+	return entry->op;
     }
 
-  return false;
+  return RISCV_FUSE_NOTHING;
+}
+
+/* Implement TARGET_SCHED_MACRO_FUSION_PAIR_P.  Return true if PREV and CURR
+   should be kept together during scheduling.  */
+
+bool
+riscv_macro_fusion_pair_p (rtx_insn *prev, rtx_insn *curr)
+{
+  enum riscv_fusion_pairs op = riscv_get_fusion_pair_type (prev, curr);
+  if (op == RISCV_FUSE_NOTHING)
+    return false;
+
+  if (dump_file)
+    fprintf (dump_file, ";; macro fusion: insn %d + insn %d -> %s\n",
+	     INSN_UID (prev), INSN_UID (curr), riscv_fusion_type_name (op));
+  return true;
 }
diff --git a/gcc/config/riscv/riscv-protos.h b/gcc/config/riscv/riscv-protos.h
index 0921b3a7618..9a775b7b32c 100644
--- a/gcc/config/riscv/riscv-protos.h
+++ b/gcc/config/riscv/riscv-protos.h
@@ -884,6 +884,8 @@ enum riscv_fusion_pairs
 
 extern bool riscv_macro_fusion_p (void);
 extern bool riscv_macro_fusion_pair_p (rtx_insn *, rtx_insn *);
+extern enum riscv_fusion_pairs riscv_get_fusion_pair_type (rtx_insn *,
+						    rtx_insn *);
 extern void riscv_sched_fusion_priority (rtx_insn *, int, int *, int *);
 extern unsigned HOST_WIDE_INT riscv_get_fusible_ops (void);
 
-- 
2.52.0