(eliminate_regs, case MULT): New case, to apply distributive law, when

needed.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@6676 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 46 insertions, 21 deletions

diff --git a/gcc/reload1.c b/gcc/reload1.c
index ac75a5181e1..90a4573282e 100644
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -2800,33 +2800,35 @@ eliminate_regs (x, mem_mode, insn)
       }
       return x;
 
-    case EXPR_LIST:
-      /* If we have something in XEXP (x, 0), the usual case, eliminate it.  */
-      if (XEXP (x, 0))
-	{
-	  new = eliminate_regs (XEXP (x, 0), mem_mode, insn);
-	  if (new != XEXP (x, 0))
-	    x = gen_rtx (EXPR_LIST, REG_NOTE_KIND (x), new, XEXP (x, 1));
-	}
+    case MULT:
+      /* If this is the product of an eliminable register and a 
+	 constant, apply the distribute law and move the constant out
+	 so that we have (plus (mult ..) ..).  This is needed in order
+	 to keep load-address insns valid.   This case is pathalogical.
+	 We ignore the possibility of overflow here.  */
+      if (GET_CODE (XEXP (x, 0)) == REG
+	  && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER
+	  && GET_CODE (XEXP (x, 1)) == CONST_INT)
+	for (ep = reg_eliminate; ep < &reg_eliminate[NUM_ELIMINABLE_REGS];
+	     ep++)
+	  if (ep->from_rtx == XEXP (x, 0) && ep->can_eliminate)
+	    {
+	      if (! mem_mode
+		  /* Refs inside notes don't count for this purpose.  */
+		  && ! (insn != 0 && (GET_CODE (insn) == EXPR_LIST
+				      || GET_CODE (insn) == INSN_LIST)))
+		ep->ref_outside_mem = 1;
+
+	      return
+		plus_constant (gen_rtx (MULT, Pmode, ep->to_rtx, XEXP (x, 1)),
+			       ep->previous_offset * INTVAL (XEXP (x, 1)));
+	    }
 
       /* ... fall through ... */
 
-    case INSN_LIST:
-      /* Now do eliminations in the rest of the chain.  If this was
-	 an EXPR_LIST, this might result in allocating more memory than is
-	 strictly needed, but it simplifies the code.  */
-      if (XEXP (x, 1))
-	{
-	  new = eliminate_regs (XEXP (x, 1), mem_mode, insn);
-	  if (new != XEXP (x, 1))
-	    return gen_rtx (GET_CODE (x), GET_MODE (x), XEXP (x, 0), new);
-	}
-      return x;
-
     case CALL:
     case COMPARE:
     case MINUS:
-    case MULT:
     case DIV:      case UDIV:
     case MOD:      case UMOD:
     case AND:      case IOR:      case XOR:
@@ -2845,6 +2847,29 @@ eliminate_regs (x, mem_mode, insn)
       }
       return x;
 
+    case EXPR_LIST:
+      /* If we have something in XEXP (x, 0), the usual case, eliminate it.  */
+      if (XEXP (x, 0))
+	{
+	  new = eliminate_regs (XEXP (x, 0), mem_mode, insn);
+	  if (new != XEXP (x, 0))
+	    x = gen_rtx (EXPR_LIST, REG_NOTE_KIND (x), new, XEXP (x, 1));
+	}
+
+      /* ... fall through ... */
+
+    case INSN_LIST:
+      /* Now do eliminations in the rest of the chain.  If this was
+	 an EXPR_LIST, this might result in allocating more memory than is
+	 strictly needed, but it simplifies the code.  */
+      if (XEXP (x, 1))
+	{
+	  new = eliminate_regs (XEXP (x, 1), mem_mode, insn);
+	  if (new != XEXP (x, 1))
+	    return gen_rtx (GET_CODE (x), GET_MODE (x), XEXP (x, 0), new);
+	}
+      return x;
+
     case PRE_INC:
     case POST_INC:
     case PRE_DEC: