Come up with debug counter for store-merging.

2019-09-18  Martin Liska  <mliska@suse.cz>

	* dbgcnt.def (store_merging): New counter.
	* gimple-ssa-store-merging.c (imm_store_chain_info::output_merged_stores):
	Use it in store merging.

From-SVN: r275867

gcc/ChangeLog

+2019-09-18  Martin Liska  <mliska@suse.cz>
+
+	* dbgcnt.def (store_merging): New counter.
+	* gimple-ssa-store-merging.c (imm_store_chain_info::output_merged_stores):
+	Use it in store merging.
+
 2019-09-17  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* config/aarch64/aarch64.c (aarch64_sched_variable_issue): New

gcc/dbgcnt.def

@@ -196,3 +196,4 @@ DEBUG_COUNTER (vect_loop)
 DEBUG_COUNTER (vect_slp)
 DEBUG_COUNTER (dom_unreachable_edges)
 DEBUG_COUNTER (match)
+DEBUG_COUNTER (store_merging)

gcc/gimple-ssa-store-merging.c

@@ -166,6 +166,7 @@
 #include "rtl.h"
 #include "expr.h"	/* For get_bit_range.  */
 #include "optabs-tree.h"
+#include "dbgcnt.h"
 #include "selftest.h"
 
 /* The maximum size (in bits) of the stores this pass should generate.  */
@@ -4195,7 +4196,8 @@ imm_store_chain_info::output_merged_stores ()
   bool ret = false;
   FOR_EACH_VEC_ELT (m_merged_store_groups, i, merged_store)
     {
-      if (output_merged_store (merged_store))
+      if (dbg_cnt (store_merging)
+	  && output_merged_store (merged_store))
 	{
 	  unsigned int j;
 	  store_immediate_info *store;