From: Bernd Schmidt <bernds@redhat.com>
Date: Tue, 3 Apr 2001 14:46:54 +0000 (+0000)
Subject: Backport reload_combine bugfix
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5d22540e59f53b55cc53229e41294e49e9ecb946;p=thirdparty%2Fgcc.git

Backport reload_combine bugfix

From-SVN: r41057
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e8552ac619bb..d12f8e2b8ca8 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -21,6 +21,10 @@
 	(get_last_value_validate) : Same.
 	(get_last_value) : Same.
 
+	Fri Mar  3 12:49:28 2000  J"orn Rennecke <amylaar@cygnus.co.uk>
+        * reload1.c (reload_combine_note_use): Handle return register USEs.
+	REG case: Handle multi-hard-register hard regs.
+
 2001-03-30  Bernd Schmidt  <bernds@redhat.com>
 
 	* jump.c (delete_barrier_successors): Fix error in last change.
diff --git a/gcc/reload1.c b/gcc/reload1.c
index f8d87517a1b6..24eb0116a7ab 100644
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -9970,6 +9970,21 @@ reload_combine_note_use (xp, insn)
 	}
       break;
 
+    case USE:
+      /* If this is the USE of a return value, we can't change it.  */
+      if (GET_CODE (XEXP (x, 0)) == REG && REG_FUNCTION_VALUE_P (XEXP (x, 0)))
+	{
+	/* Mark the return register as used in an unknown fashion.  */
+	  rtx reg = XEXP (x, 0);
+	  int regno = REGNO (reg);
+	  int nregs = HARD_REGNO_NREGS (regno, GET_MODE (reg));
+
+	  while (--nregs >= 0)
+	    reg_state[regno + nregs].use_index = -1;
+	  return;
+	}
+      break;
+
     case CLOBBER:
       if (GET_CODE (SET_DEST (x)) == REG)
 	return;
@@ -9986,12 +10001,23 @@ reload_combine_note_use (xp, insn)
       {
 	int regno = REGNO (x);
 	int use_index;
+	int nregs;
 
 	/* Some spurious USEs of pseudo registers might remain.
 	   Just ignore them.  */
 	if (regno >= FIRST_PSEUDO_REGISTER)
 	  return;
 
+	nregs = HARD_REGNO_NREGS (regno, GET_MODE (x));
+
+	/* We can't substitute into multi-hard-reg uses.  */
+	if (nregs > 1)
+	  {
+	    while (--nregs >= 0)
+	      reg_state[regno + nregs].use_index = -1;
+	    return;
+	  }
+
 	/* If this register is already used in some unknown fashion, we
 	   can't do anything.
 	   If we decrement the index from zero to -1, we can't store more