[spu] Fix ICEs with complex integer types (4.4 regression)

["Ulrich Weigand" <uweigand at de dot ibm dot com>]

Hello,

the following patch:

2009-01-11  Adam Nemet  <anemet@caviumnetworks.com>

        * expmed.c (store_bit_field_1): Properly truncate the paradoxical
        subreg of op0 to the original op0.

http://gcc.gnu.org/ml/gcc-patches/2008-12/msg00766.html

exposes a problem on the SPU that causes internal compiler errors in
several test cases using complex integer function return types.

The problem is caused by expmed.c:store_bit_field_1 creating a TImode
subreg of a pseudo of some complex integer type (or the integer type
of equivalent length).  It seems to me that these subregs are not
actually valid in the first place, because the SPU CANNOT_CHANGE_MODE
macro rejects it (because integer values of smaller size do *not*
occupy the low part of a TImode register on the SPU), however, the
store_bit_field_1 logic never checks for this.

Now, the SPU back-end has some logic to cope with those paradoxical
subregs anyway (the valid_subreg checks in spu_expand_mov, and the
adjust_operand logic in the insv/extv expanders).  However, the
patch mentioned above exposes one situation that is currently not
covered by that logic: the trunctidi expander is called on a 
source that is a TImode paradoxical subreg of a complex integer
mode.  This runs into a failed assertion in spu_expand_mov, where
it assumes that the inner mode must be integral.

The following patch extends the spu_expand_mov logic to also
handle non-integral modes, by performing the shift in a same
size integral mode.  This fixes the test suite ICEs.

(Longer term, the middle-end should really be fixed to not generate
those subregs in the first place.  But for now, I think the patch
below is the conservative fix to get SPU working again ...)

Tested on spu-elf with no regressions, fixes the following FAILs:

FAIL: gcc.c-torture/compile/pr27889.c  -O0  (internal compiler error)
FAIL: gcc.c-torture/compile/pr27889.c  -O0  (test for excess errors)
FAIL: gcc.c-torture/compile/pr27889.c  -O1  (internal compiler error)
FAIL: gcc.c-torture/compile/pr27889.c  -O1  (test for excess errors)
FAIL: gcc.c-torture/compile/pr27889.c  -O2  (internal compiler error)
FAIL: gcc.c-torture/compile/pr27889.c  -O2  (test for excess errors)
FAIL: gcc.c-torture/compile/pr27889.c  -O3 -fomit-frame-pointer  (internal compiler error)
FAIL: gcc.c-torture/compile/pr27889.c  -O3 -fomit-frame-pointer  (test for excess errors)
FAIL: gcc.c-torture/compile/pr27889.c  -O3 -g  (internal compiler error)
FAIL: gcc.c-torture/compile/pr27889.c  -O3 -g  (test for excess errors)
FAIL: gcc.c-torture/compile/pr27889.c  -Os  (internal compiler error)
FAIL: gcc.c-torture/compile/pr27889.c  -Os  (test for excess errors)
FAIL: gcc.c-torture/execute/20050121-1.c compilation,  -O0  (internal compiler error)
FAIL: gcc.c-torture/execute/20050121-1.c compilation,  -O1  (internal compiler error)
FAIL: gcc.c-torture/execute/20050121-1.c compilation,  -O2  (internal compiler error)
FAIL: gcc.c-torture/execute/20050121-1.c compilation,  -O3 -fomit-frame-pointer  (internal compiler error)
FAIL: gcc.c-torture/execute/20050121-1.c compilation,  -O3 -g  (internal compiler error)
FAIL: gcc.c-torture/execute/20050121-1.c compilation,  -Os  (internal compiler error)
FAIL: gcc.c-torture/execute/complex-6.c compilation,  -O0  (internal compiler error)
FAIL: gcc.c-torture/execute/complex-6.c compilation,  -O1  (internal compiler error)
FAIL: gcc.c-torture/execute/complex-6.c compilation,  -O2  (internal compiler error)
FAIL: gcc.c-torture/execute/complex-6.c compilation,  -O3 -fomit-frame-pointer  (internal compiler error)
FAIL: gcc.c-torture/execute/complex-6.c compilation,  -O3 -g  (internal compiler error)
FAIL: gcc.c-torture/execute/complex-6.c compilation,  -Os  (internal compiler error)
FAIL: gcc.dg/compat/scalar-return-3 c_compat_y_tst.o compile,  (internal compiler error)
FAIL: gcc.dg/compat/scalar-return-4 c_compat_y_tst.o compile,  (internal compiler error)
FAIL: gcc.dg/fold-mulconj-1.c (internal compiler error)
FAIL: gcc.dg/fold-mulconj-1.c (test for excess errors)

OK for mainline?

Bye,
Ulrich


ChangeLog:

	* config/spu/spu.c (spu_expand_mov): Handle invalid subregs
	of non-integer mode as well.


Index: gcc/config/spu/spu.c
===================================================================
*** gcc/config/spu/spu.c	(revision 144550)
--- gcc/config/spu/spu.c	(working copy)
*************** spu_expand_mov (rtx * ops, enum machine_
*** 4114,4130 ****
    if (GET_CODE (ops[1]) == SUBREG && !valid_subreg (ops[1]))
      {
        rtx from = SUBREG_REG (ops[1]);
!       enum machine_mode imode = GET_MODE (from);
  
        gcc_assert (GET_MODE_CLASS (mode) == MODE_INT
  		  && GET_MODE_CLASS (imode) == MODE_INT
  		  && subreg_lowpart_p (ops[1]));
  
        if (GET_MODE_SIZE (imode) < 4)
! 	{
! 	  from = gen_rtx_SUBREG (SImode, from, 0);
! 	  imode = SImode;
! 	}
  
        if (GET_MODE_SIZE (mode) < GET_MODE_SIZE (imode))
  	{
--- 4114,4129 ----
    if (GET_CODE (ops[1]) == SUBREG && !valid_subreg (ops[1]))
      {
        rtx from = SUBREG_REG (ops[1]);
!       enum machine_mode imode = int_mode_for_mode (GET_MODE (from));
  
        gcc_assert (GET_MODE_CLASS (mode) == MODE_INT
  		  && GET_MODE_CLASS (imode) == MODE_INT
  		  && subreg_lowpart_p (ops[1]));
  
        if (GET_MODE_SIZE (imode) < 4)
! 	imode = SImode;
!       if (imode != GET_MODE (from))
! 	from = gen_rtx_SUBREG (imode, from, 0);
  
        if (GET_MODE_SIZE (mode) < GET_MODE_SIZE (imode))
  	{
-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com