rs6000-p8swap.c (rs6000_analyze_swaps): Rebuild ud- and du-chains between phases.

2019-03-08  Bill Schmidt  <wschmidt@linux.ibm.com>

	* config/rs6000/rs6000-p8swap.c (rs6000_analyze_swaps): Rebuild
	ud- and du-chains between phases.

From-SVN: r269505

gcc/ChangeLog

+2019-03-08  Bill Schmidt  <wschmidt@linux.ibm.com>
+
+	* config/rs6000/rs6000-p8swap.c (rs6000_analyze_swaps): Rebuild
+	ud- and du-chains between phases.
+
 2019-03-08  Richard Sandiford  <richard.sandiford@arm.com>
 
 	PR debug/89631

gcc/config/rs6000/rs6000-p8swap.c

@@ -2316,7 +2316,14 @@ rs6000_analyze_swaps (function *fun)
 
   /* Pre-pass to recombine lvx and stvx patterns so we don't lose info.  */
   recombine_lvx_stvx_patterns (fun);
+
+  /* Rebuild ud- and du-chains.  */
+  df_remove_problem (df_chain);
   df_process_deferred_rescans ();
+  df_set_flags (DF_RD_PRUNE_DEAD_DEFS);
+  df_chain_add_problem (DF_DU_CHAIN | DF_UD_CHAIN);
+  df_analyze ();
+  df_set_flags (DF_DEFER_INSN_RESCAN);
 
   /* Allocate structure to represent webs of insns.  */
   insn_entry = XCNEWVEC (swap_web_entry, get_max_uid ());