[backport proposed but not yet approved or applied patch for an old reload regression <mikpe@it.uu.se>]

List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>
Date: Fri, 03 May 2013 07:42:16 -0400
From: Joern Rennecke <joern dot rennecke at embecosm dot com>
Subject: RFA: fix find_valid_class to accept classes w/out last hard reg

In revision 91802, the tests in find_valid_class got garbled so that with
n > 0, it won't accept a class that does not include  
FIRST_PSEUDO_REGISTER - 1.

The attached patch restores the status quo ante of allowing register classes
that stop earlier.

This fixes the compile/pr55921.c failures for avr.

bootstrapped/regtested on i686-pc-linux-gnu.
regtested on i686-pc-linuc-gnu X sh-elf.

gcc/

2013-05-02  Joern Rennecke <joern.rennecke@embecosm.com>

	* reload.c (find_valid_class): Allow classes that do not include
	FIRST_PSEUDO_REGISTER - 1.

--- gcc-4.8.0/gcc/reload.c.~1~	2013-02-04 17:23:38.000000000 +0100
+++ gcc-4.8.0/gcc/reload.c	2013-05-04 12:31:42.715330882 +0200
@@ -680,8 +680,8 @@ find_valid_class (enum machine_mode oute
 	    if (HARD_REGNO_MODE_OK (regno, inner))
 	      {
 		good = 1;
-		if (! TEST_HARD_REG_BIT (reg_class_contents[rclass], regno + n)
-		    || ! HARD_REGNO_MODE_OK (regno + n, outer))
+		if (TEST_HARD_REG_BIT (reg_class_contents[rclass], regno + n)
+		    && ! HARD_REGNO_MODE_OK (regno + n, outer))
 		  bad = 1;
 	      }
 	  }