2015-06-28 Chung-Lin Tang <cltang@codesourcery.com>

	    Sandra Loosemore <sandra@codesourcery.com>

	gcc/
	* regrename.h (regrename_do_replace): Change to return bool.
	* regrename.c (rename_chains): Check return value of
	regname_do_replace.
	(regrename_do_replace): Re-validate the modified insns and
	return bool status.
	* config/aarch64/cortex-a57-fma-steering.c (rename_single_chain):
	Update to match rename_chains changes.
	* config/c6x/c6x.c (try_rename_operands): Assert that
	regrename_do_replace returns true.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@225106 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 29 insertions, 11 deletions

diff --git a/gcc/regrename.c b/gcc/regrename.c
index 0cba8ded8c2..6c7d650ea83 100644
--- a/gcc/regrename.c
+++ b/gcc/regrename.c
@@ -496,12 +496,20 @@ rename_chains (void)
 	  continue;
 	}
 
-      if (dump_file)
-	fprintf (dump_file, ", renamed as %s\n", reg_names[best_new_reg]);
-
-      regrename_do_replace (this_head, best_new_reg);
-      tick[best_new_reg] = ++this_tick;
-      df_set_regs_ever_live (best_new_reg, true);
+      if (regrename_do_replace (this_head, best_new_reg))
+	{
+	  if (dump_file)
+	    fprintf (dump_file, ", renamed as %s\n", reg_names[best_new_reg]);
+	  tick[best_new_reg] = ++this_tick;
+	  df_set_regs_ever_live (best_new_reg, true);
+	}
+      else
+	{
+	  if (dump_file)
+	    fprintf (dump_file, ", renaming as %s failed\n",
+		     reg_names[best_new_reg]);
+	  tick[reg] = ++this_tick;
+	}
     }
 }
 
@@ -927,7 +935,13 @@ regrename_analyze (bitmap bb_mask)
     bb->aux = NULL;
 }
 
-void
+/* Attempt to replace all uses of the register in the chain beginning with
+   HEAD with REG.  Returns true on success and false if the replacement is
+   rejected because the insns would not validate.  The latter can happen
+   e.g. if a match_parallel predicate enforces restrictions on register
+   numbering in its subpatterns.  */
+
+bool
 regrename_do_replace (struct du_head *head, int reg)
 {
   struct du_chain *chain;
@@ -941,22 +955,26 @@ regrename_do_replace (struct du_head *head, int reg)
       int reg_ptr = REG_POINTER (*chain->loc);
 
       if (DEBUG_INSN_P (chain->insn) && REGNO (*chain->loc) != base_regno)
-	INSN_VAR_LOCATION_LOC (chain->insn) = gen_rtx_UNKNOWN_VAR_LOC ();
+	validate_change (chain->insn, &(INSN_VAR_LOCATION_LOC (chain->insn)),
+			 gen_rtx_UNKNOWN_VAR_LOC (), true);
       else
 	{
-	  *chain->loc = gen_raw_REG (GET_MODE (*chain->loc), reg);
+	  validate_change (chain->insn, chain->loc, 
+			   gen_raw_REG (GET_MODE (*chain->loc), reg), true);
 	  if (regno >= FIRST_PSEUDO_REGISTER)
 	    ORIGINAL_REGNO (*chain->loc) = regno;
 	  REG_ATTRS (*chain->loc) = attr;
 	  REG_POINTER (*chain->loc) = reg_ptr;
 	}
-
-      df_insn_rescan (chain->insn);
     }
 
+  if (!apply_change_group ())
+    return false;
+
   mode = GET_MODE (*head->first->loc);
   head->regno = reg;
   head->nregs = hard_regno_nregs[reg][mode];
+  return true;
 }