From: Chris Lattner <sabre@nondot.org>
Date: Wed, 29 May 2002 16:23:28 +0000 (+0000)
Subject: ssa.c (rename_insn_1): Rename uses of undefined registers to prevent confusion if... 
X-Git-Tag: releases/gcc-3.3.0~4736
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=45b1f7c746372e7dc48d79c9b5089ce12cbef1e5;p=thirdparty%2Fgcc.git

ssa.c (rename_insn_1): Rename uses of undefined registers to prevent confusion if/when...

        * ssa.c (rename_insn_1): Rename uses of undefined registers to
        prevent confusion if/when the register is defined.

From-SVN: r54002
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5c6455038e71..9ff0f270de46 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2002-05-29  Chris Lattner  <sabre@nondot.org>
+
+        * ssa.c (rename_insn_1): Rename uses of undefined registers to
+        prevent confusion if/when the register is defined.
+
 2002-05-29  Hans-Peter Nilsson  <hp@axis.com>
 
 	PR target/6838
diff --git a/gcc/ssa.c b/gcc/ssa.c
index 835bf55ce0c1..b81a8ac78312 100644
--- a/gcc/ssa.c
+++ b/gcc/ssa.c
@@ -916,18 +916,26 @@ rename_insn_1 (ptr, data)
       }
 
     case REG:
-      if (CONVERT_REGISTER_TO_SSA_P (REGNO (x)) &&
-	  REGNO (x) < ssa_max_reg_num)
+      if (CONVERT_REGISTER_TO_SSA_P (REGNO (x))
+	  && REGNO (x) < ssa_max_reg_num)
 	{
 	  rtx new_reg = ssa_rename_to_lookup (x);
 
-	  if (new_reg != NULL_RTX && new_reg != RENAME_NO_RTX)
+	  if (new_reg != RENAME_NO_RTX)
 	    {
-	      if (GET_MODE (x) != GET_MODE (new_reg))
-		abort ();
-	      *ptr = new_reg;
+	      if (new_reg != NULL_RTX)
+		{
+		  if (GET_MODE (x) != GET_MODE (new_reg))
+		    abort ();
+		  *ptr = new_reg;
+		}
+	      else
+		{
+		  /* Undefined value used, rename it to a new pseudo register so
+		     that it cannot conflict with an existing register */
+		  *ptr = gen_reg_rtx (GET_MODE(x));
+		}
 	    }
-	  /* Else this is a use before a set.  Warn?  */
 	}
       return -1;