Patch for mips offs > 16bit, *kludge* for egcs-1.1.2 release

[Hans-Peter Nilsson <hp at bitrange dot com>]

I took a shot at this, even though I know diddley about mips
(not really necessary when you have the GCC machine description,
and has ignorance ever stopped anybody anyway? 1/2 :-)

Configured for --target=mipsel-unknown-netbsd (host =
i686-pc-linux-gnulibc1), the bug shows up with the test-cases in
<URL:http://egcs.cygnus.com/ml/egcs-bugs/1999-02/msg00786.html>
and <URL:http://www.cygnus.com/ml/egcs-bugs/1998-Oct/0928.html>,
running with no optimization; no flags at all to cc1.

There is an analysis of the problem in
<URL:http://www.cygnus.com/ml/egcs-bugs/1998-Oct/0928.html>, but
I don't really agree with that (mips-centric) analysis except
which change that caused the failure; the main problem is not
any specific badness in the mips port.
 The problem is that in the quoted change (1.76 of expr.c) in
expand_assignment and expand_expr (maybe elsewhere).  The movP
(movsi, movdi) pattern is used through a call to emit_move_insn
without making sure that the input operand is a valid operand
for that pattern.
 In this case it is an address, a (plus ...)-expression.  This
is not valid input to emit_move_insn, (which passes it on to
gen_movsi, or gen_movdi for 64-bit targets, without checking or
correcting for predicates).
 Much later, it fails to be recognized -- unless optimizing, in
which case combine will do tricks and reshape the operands so it
will be recognized.


For the release-branch, here's a patch that does *not* try to
correct the general badness (next patch), but instead try and
confine a fix for the mips target only; (included here).  If the
kludgyness of this patch causes indigestion, then please look at
the general correction in expr.c with the *next* patch (similar
subject); I do prefer that one and believe it is more correct.

With this patch, those two testcases seem to work (beware of my
mips-cluelessness).  Nothing else tested; I don't have a mips
machine.  Any mips people around?

Sun Feb 28 11:30:57 1999  Hans-Peter Nilsson  <hp@bitrange.com>

	* config/mips/mips.md (movsi, movdi: Adjust operand 1 if not
	general_operand.

===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/config/mips/mips.md,v
retrieving revision 1.31.2.1
diff -p -c -r1.31.2.1 mips.md
*** mips.md	1998/07/20 22:15:33	1.31.2.1
--- mips.md	1999/02/28 11:28:49
***************
*** 3,9 ****
  ;;  Changes by       Michael Meissner, meissner@osf.org
  ;;  64 bit r4000 support by Ian Lance Taylor, ian@cygnus.com, and
  ;;  Brendan Eich, brendan@microunity.com.
! ;;  Copyright (C) 1989, 90-97, 1998 Free Software Foundation, Inc.
  
  ;; This file is part of GNU CC.
  
--- 3,9 ----
  ;;  Changes by       Michael Meissner, meissner@osf.org
  ;;  64 bit r4000 support by Ian Lance Taylor, ian@cygnus.com, and
  ;;  Brendan Eich, brendan@microunity.com.
! ;;  Copyright (C) 1989, 90-98, 1999 Free Software Foundation, Inc.
  
  ;; This file is part of GNU CC.
  
*************** move\\t%0,%z4\\n\\
*** 4500,4505 ****
--- 4500,4514 ----
        emit_move_insn (operands[0], temp);
        DONE;
      }
+ 
+   /* Kludge for a bug in egcs 1.1.2 causing source operand with
+      unchecked predicate to appear here. */
+   if (! general_operand (operands[1], DImode)
+       && reload_in_progress == 0 && reload_completed == 0)
+     {
+       emit_move_insn (operands[0], force_operand (operands[1], NULL_RTX));
+       DONE;
+     }
  }")
  
  ;; For mips16, we need a special case to handle storing $31 into
*************** move\\t%0,%z4\\n\\
*** 4913,4918 ****
--- 4922,4936 ----
      {
        rtx temp = force_reg (SImode, operands[1]);
        emit_move_insn (operands[0], temp);
+       DONE;
+     }
+ 
+   /* Kludge for a bug in egcs 1.1.2 causing source operand with
+      unchecked predicate to appear here. */
+   if (! general_operand (operands[1], SImode)
+       && reload_in_progress == 0 && reload_completed == 0)
+     {
+       emit_move_insn (operands[0], force_operand (operands[1], NULL_RTX));
        DONE;
      }
  }")

brgds, H-P