From: Jeffrey A Law <law@cygnus.com>
Date: Wed, 5 Nov 1997 21:17:36 +0000 (+0000)
Subject: alias.c (find_base_value): Only return the known base value for pseudo registers.
X-Git-Tag: releases/egcs-1.0.0~159
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b25cf9d2d4f22c496c2216395a5a743d079ca3e1;p=thirdparty%2Fgcc.git

alias.c (find_base_value): Only return the known base value for pseudo registers.

        * alias.c (find_base_value): Only return the known base value for
        pseudo registers.

From-SVN: r16343
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 686681cabb98..855caae8f852 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -2,6 +2,9 @@ Wed Nov  5 01:42:12 1997  Jeffrey A Law  (law@cygnus.com)
 
 	* version.c: Bump for snapshot.
 
+	* alias.c (find_base_value): Only return the known base value for
+	pseudo registers.
+
 Tue Nov  4 16:07:15 1997  Jeffrey A Law  (law@cygnus.com)
 
 	* fixincludes: Fix "hypot" prototype in NeXT math.h.
diff --git a/gcc/alias.c b/gcc/alias.c
index 0943444185a2..025da501a427 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -102,10 +102,14 @@ find_base_value (src)
       if (REGNO (src) < FIRST_PSEUDO_REGISTER && copying_arguments)
 	return new_reg_base_value[REGNO (src)];
 
-      /* If this REG is related to a known base value, return it.
-	 This must happen after the arg register check above to avoid
-	 circular set chains.  */
-      if (reg_base_value[REGNO (src)])
+      /* If a pseudo has a known base value, return it.  Do not do this
+	 for hard regs since it can result in a circular dependency
+	 chain for registers which have values at function entry.
+
+	 The test above is not sufficient because the scheduler may move
+	 a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN.  */
+      if (REGNO (src) >= FIRST_PSEUDO_REGISTER
+	  && reg_base_value[REGNO (src)])
 	return reg_base_value[REGNO (src)];
 
       return src;