Handle equivalences that have been obscured by gcse:

	* reload1.c (reload): Handle equivalences set up in multiple places.
	* local-alloc.c (reg_equiv_init_insns): New variable.
	(no_equiv): New function.
	(update_equiv_regs): Handle equivalences set up in multiple places.
	Don't ignore an insn just because its destination is likely to be
	spilled.

From-SVN: r23610

1 files changed, 27 insertions, 16 deletions

diff --git a/gcc/reload1.c b/gcc/reload1.c
index ea8bc1f..5df3c15 100644
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -114,7 +114,7 @@ rtx *reg_equiv_mem;
 /* Widest width in which each pseudo reg is referred to (via subreg).  */
 static int *reg_max_ref_width;
 
-/* Element N is the insn that initialized reg N from its equivalent
+/* Element N is the list of insns that initialized reg N from its equivalent
    constant or memory slot.  */
 static rtx *reg_equiv_init;
 
@@ -710,7 +710,8 @@ reload (first, global, dumpfile)
 		     So don't mark this insn now.  */
 		  if (GET_CODE (x) != MEM
 		      || rtx_equal_p (SET_SRC (set), x))
-		    reg_equiv_init[i] = insn;
+		    reg_equiv_init[i]
+		      = gen_rtx_INSN_LIST (VOIDmode, insn, reg_equiv_init[i]);
 		}
 	    }
 	}
@@ -722,7 +723,9 @@ reload (first, global, dumpfile)
 	       && reg_equiv_memory_loc[REGNO (SET_SRC (set))]
 	       && rtx_equal_p (SET_DEST (set),
 			       reg_equiv_memory_loc[REGNO (SET_SRC (set))]))
-	reg_equiv_init[REGNO (SET_SRC (set))] = insn;
+	reg_equiv_init[REGNO (SET_SRC (set))]
+	  = gen_rtx_INSN_LIST (VOIDmode, insn,
+			       reg_equiv_init[REGNO (SET_SRC (set))]);
 
       if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
 	scan_paradoxical_subregs (PATTERN (insn));
@@ -971,22 +974,30 @@ reload (first, global, dumpfile)
      If that insn didn't set the register (i.e., it copied the register to
      memory), just delete that insn instead of the equivalencing insn plus
      anything now dead.  If we call delete_dead_insn on that insn, we may
-     delete the insn that actually sets the register if the register die
+     delete the insn that actually sets the register if the register dies
      there and that is incorrect.  */
 
   for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
-    if (reg_renumber[i] < 0 && reg_equiv_init[i] != 0
-	&& GET_CODE (reg_equiv_init[i]) != NOTE)
-      {
-	if (reg_set_p (regno_reg_rtx[i], PATTERN (reg_equiv_init[i])))
-	  delete_dead_insn (reg_equiv_init[i]);
-	else
-	  {
-	    PUT_CODE (reg_equiv_init[i], NOTE);
-	    NOTE_SOURCE_FILE (reg_equiv_init[i]) = 0;
-	    NOTE_LINE_NUMBER (reg_equiv_init[i]) = NOTE_INSN_DELETED;
-	  }
-      }
+    {
+      if (reg_renumber[i] < 0 && reg_equiv_init[i] != 0)
+	{
+	  rtx list;
+	  for (list = reg_equiv_init[i]; list; list = XEXP (list, 1))
+	    {
+	      rtx equiv_insn = XEXP (list, 0);
+	      if (GET_CODE (equiv_insn) == NOTE)
+		continue;
+	      if (reg_set_p (regno_reg_rtx[i], PATTERN (equiv_insn)))
+		delete_dead_insn (equiv_insn);
+	      else
+		{
+		  PUT_CODE (equiv_insn, NOTE);
+		  NOTE_SOURCE_FILE (equiv_insn) = 0;
+		  NOTE_LINE_NUMBER (equiv_insn) = NOTE_INSN_DELETED;
+		}
+	    }
+	}
+    }
 
   /* Use the reload registers where necessary
      by generating move instructions to move the must-be-register