From: "Ulrich Weigand" <uweigand@de.ibm.com>
To: ebotcazou@adacore.com (Eric Botcazou)
Cc: iant@google.com, gcc-patches@gcc.gnu.org,
trevor_smigiel@playstation.sony.com,
andrew_pinski@playstation.sony.com
Subject: [PATCH, v2] Re: [PATCH] Fix ICE in simplify_immed_subreg on SPU
Date: Thu, 26 Jun 2008 22:15:00 -0000 [thread overview]
Message-ID: <200806262209.m5QM9Ww5024891@d12av02.megacenter.de.ibm.com> (raw)
In-Reply-To: <200806160027.42235.ebotcazou@adacore.com> from "Eric Botcazou" at Jun 16, 2008 12:27:42 AM
Eric Botcazou wrote:
> > I think I'm with Ulrich here. A CONST_VECTOR containing a CONST seems
> > reasonable to me. Eric, can you clarify what you see as the problem?
>
> I don't see the point in changing the semantics of CONST_VECTOR because of
> a IMO non-representative testcase.
I've looked at this again in more detail, and it seems that there is
indeed the pervasive assumption that CONST_VECTOR elements can only
be CONST_INT, CONST_DOUBLE, and CONST_FIXED. For example, dwarf2out.c
cannot handle anything else when constructing an DW_AT_const_value
attribute refering to a CONST_VECTOR.
While I still think it would be better to allow any legitimate constant
as member of a CONST_VECTOR, this would require non-trivial changes to
dwarf2out.c and a couple of other places. Therefore, for now I think
it is best to change the SPU back-end to avoid generating CONST_VECTOR
expressions that are invalid according to the current middle-end rules.
At some later time those middle-end rules could be relaxed ...
The following (SPU back-end only) patch implements this. While this
might result in somewhat less efficient code being generated for
certain case, those cases should be rather rare.
Trevor/Andrew, what are your thoughts about this? Would this be OK
for mainline and 4.3?
Tested on spu-elf with no regressions, fixes the pr34856 FAILs.
Bye,
Ulrich
ChangeLog:
PR target/34856
* config/spu/spu.c (spu_builtin_splats): Do not generate
invalid CONST_VECTOR expressions.
(spu_expand_vector_init): Likewise.
Index: gcc/config/spu/spu.c
===================================================================
*** gcc/config/spu/spu.c (revision 136912)
--- gcc/config/spu/spu.c (working copy)
*************** spu_builtin_splats (rtx ops[])
*** 4576,4590 ****
constant_to_array (GET_MODE_INNER (mode), ops[1], arr);
emit_move_insn (ops[0], array_to_constant (mode, arr));
}
- else if (!flag_pic && GET_MODE (ops[0]) == V4SImode && CONSTANT_P (ops[1]))
- {
- rtvec v = rtvec_alloc (4);
- RTVEC_ELT (v, 0) = ops[1];
- RTVEC_ELT (v, 1) = ops[1];
- RTVEC_ELT (v, 2) = ops[1];
- RTVEC_ELT (v, 3) = ops[1];
- emit_move_insn (ops[0], gen_rtx_CONST_VECTOR (mode, v));
- }
else
{
rtx reg = gen_reg_rtx (TImode);
--- 4576,4581 ----
*************** spu_expand_vector_init (rtx target, rtx
*** 4903,4909 ****
for (i = 0; i < n_elts; ++i)
{
x = XVECEXP (vals, 0, i);
! if (!CONSTANT_P (x))
++n_var;
else
{
--- 4894,4902 ----
for (i = 0; i < n_elts; ++i)
{
x = XVECEXP (vals, 0, i);
! if (!(CONST_INT_P (x)
! || GET_CODE (x) == CONST_DOUBLE
! || GET_CODE (x) == CONST_FIXED))
++n_var;
else
{
*************** spu_expand_vector_init (rtx target, rtx
*** 4940,4947 ****
/* fill empty slots with the first constant, this increases
our chance of using splats in the recursive call below. */
for (i = 0; i < n_elts; ++i)
! if (!CONSTANT_P (XVECEXP (constant_parts_rtx, 0, i)))
! XVECEXP (constant_parts_rtx, 0, i) = first_constant;
spu_expand_vector_init (target, constant_parts_rtx);
}
--- 4933,4945 ----
/* fill empty slots with the first constant, this increases
our chance of using splats in the recursive call below. */
for (i = 0; i < n_elts; ++i)
! {
! x = XVECEXP (constant_parts_rtx, 0, i);
! if (!(CONST_INT_P (x)
! || GET_CODE (x) == CONST_DOUBLE
! || GET_CODE (x) == CONST_FIXED))
! XVECEXP (constant_parts_rtx, 0, i) = first_constant;
! }
spu_expand_vector_init (target, constant_parts_rtx);
}
*************** spu_expand_vector_init (rtx target, rtx
*** 4957,4963 ****
for (i = 0; i < n_elts; ++i)
{
x = XVECEXP (vals, 0, i);
! if (!CONSTANT_P (x))
{
if (!register_operand (x, GET_MODE (x)))
x = force_reg (GET_MODE (x), x);
--- 4955,4963 ----
for (i = 0; i < n_elts; ++i)
{
x = XVECEXP (vals, 0, i);
! if (!(CONST_INT_P (x)
! || GET_CODE (x) == CONST_DOUBLE
! || GET_CODE (x) == CONST_FIXED))
{
if (!register_operand (x, GET_MODE (x)))
x = force_reg (GET_MODE (x), x);
--
Dr. Ulrich Weigand
GNU Toolchain for Linux on System z and Cell BE
Ulrich.Weigand@de.ibm.com
next prev parent reply other threads:[~2008-06-26 22:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-15 15:53 Ulrich Weigand
2008-06-15 17:27 ` Eric Botcazou
2008-06-15 17:43 ` Ulrich Weigand
2008-06-15 22:24 ` Eric Botcazou
2008-06-15 22:25 ` Ian Lance Taylor
2008-06-15 22:45 ` Eric Botcazou
2008-06-15 22:49 ` Andrew Pinski
2008-06-26 22:15 ` Ulrich Weigand [this message]
2008-06-26 23:14 ` [PATCH, v2] " trevor_smigiel
2008-06-27 7:05 ` Eric Botcazou
2008-06-28 17:53 ` Ulrich Weigand
2008-06-30 8:27 ` Eric Botcazou
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