Fix ia64-linux compiler abort on perl.

	* reload.c (push_reload): Use CLASS_CANNOT_CHANGE_MODE_P in addition
	to CLASS_CANNOT_CHANGE_MODE.
	* config/ia64/ia64.h (CLASS_CANNOT_CHANGE_MODE_P): True only if the
	mode classes are different.

From-SVN: r36256

gcc/ChangeLog

+2000-09-07  Jim Wilson  <wilson@cygnus.com>
+
+	* reload.c (push_reload): Use CLASS_CANNOT_CHANGE_MODE_P in addition
+	to CLASS_CANNOT_CHANGE_MODE.
+	* config/ia64/ia64.h (CLASS_CANNOT_CHANGE_MODE_P): True only if the
+	mode classes are different.
+
 2000-09-07  Zack Weinberg  <zack@wolery.cumb.org>
 
 	* cpplib.h (struct cpp_options): Add user_label_prefix member,

gcc/config/ia64/ia64.h

@@ -1055,9 +1055,12 @@ enum reg_class
 
 #define CLASS_CANNOT_CHANGE_MODE        FR_REGS
 
-/* Defines illegal mode changes for CLASS_CANNOT_CHANGE_MODE.  */
+/* Defines illegal mode changes for CLASS_CANNOT_CHANGE_MODE.
+   In FP regs, we can't change FP values to integer values and vice
+   versa, but we can change e.g. DImode to SImode.  */
 
-#define CLASS_CANNOT_CHANGE_MODE_P(FROM,TO) 1
+#define CLASS_CANNOT_CHANGE_MODE_P(FROM,TO) \
+  (GET_MODE_CLASS (FROM) != GET_MODE_CLASS (TO))
 
 /* A C expression that defines the machine-dependent operand constraint
    letters (`I', `J', `K', .. 'P') that specify particular ranges of

gcc/reload.c

@@ -946,7 +946,8 @@ push_reload (in, out, inloc, outloc, class,
   if (in != 0 && GET_CODE (in) == SUBREG
       && (SUBREG_WORD (in) == 0 || strict_low)
 #ifdef CLASS_CANNOT_CHANGE_MODE
-      && class != CLASS_CANNOT_CHANGE_MODE
+      && (class != CLASS_CANNOT_CHANGE_MODE
+	  || ! CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (in)), inmode))
 #endif
       && (CONSTANT_P (SUBREG_REG (in))
 	  || GET_CODE (SUBREG_REG (in)) == PLUS
@@ -1051,7 +1052,9 @@ push_reload (in, out, inloc, outloc, class,
   if (out != 0 && GET_CODE (out) == SUBREG
       && (SUBREG_WORD (out) == 0 || strict_low)
 #ifdef CLASS_CANNOT_CHANGE_MODE
-      && class != CLASS_CANNOT_CHANGE_MODE
+      && (class != CLASS_CANNOT_CHANGE_MODE
+	  || ! CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (out)),
+					   outmode))
 #endif
       && (CONSTANT_P (SUBREG_REG (out))
 	  || strict_low