On Wed, Aug 19, 2015 at 8:45 AM, Alexandre Oliva <aol...@redhat.com> wrote:
> On Aug 18, 2015, Alexandre Oliva <aol...@redhat.com> wrote:
>
>>>> On Aug 17, 2015, Christophe Lyon <christophe.l...@linaro.org> wrote:
>>>>> Since this was committed (r226901), I can see that the compiler build
>>>>> fails for armeb targets, when building libgcc:
>
>> This patch fixes this particular case. I'll also add this configuration
>> to the cross build tests I'm going to rerun shortly, before submitting a
>> followup formally, to see whether other non-MEM mems need to be handled
>> explicitly.
>
> On Aug 17, 2015, Andreas Schwab <sch...@linux-m68k.org> wrote:
>
>> Andreas Schwab <sch...@linux-m68k.org> writes:
>
>>> Alexandre Oliva <aol...@redhat.com> writes:
>>>
>>>> Would you be so kind as to give it a spin on a m68k native? TIA,
>>>
>>> I tried it on ia64, and it falls flat on the floor.
>
>> It fixes the m68k failures, though.
>
> On Aug 17, 2015, Alexandre Oliva <aol...@redhat.com> wrote:
>
>>> I tried it on ia64, and it falls flat on the floor.
>
>> Doh, I see a logic flaw in the patch I posted.
>
> There were other shortcomings in the snippets I posted before, revealed
> by testing on on various other targets: remaining BLKmode asserts,
> failure to deal with parms without a default def and split complex args
> with an unassigned stack address. This patch fixes them all.
>
> It was regstrapped on x86_64-linux-gnu, i686-linux-gnu, ppc64-linux-gnu,
> ppc64el-linux-gnu, and further tested with a compile-only 'make all' on
> a binutils+gcc+newlib tree on all tens of cross targets mentioned
> before, plus the armeb configuration Christophe mentioned.
>
> Ok to install?
Ok.
Thanks,
Richard.
>
> [PR64164] fix regressions reported on m68k and armeb
>
> From: Alexandre Oliva <aol...@redhat.com>
>
> Defer stack slot address assignment for all parms that can't live in
> pseudos, and accept pseudos assignments in assign_param_setup_block.
>
> for gcc/ChangeLog
>
> PR rtl-optimization/64164
> * cfgexpand.c (parm_maybe_byref_p): Renamed to...
> (parm_in_stack_slot_p): ... this. Disregard mode, what
> matters is whether the parm will live in a pseudo or a stack
> slot.
> (expand_one_ssa_partition): Deal with params without a default
> def. Disregard mode.
> * cfgexpand.h: Renamed function declaration.
> * tree-ssa-coalesce.c: Adjust.
> * function.c (split_complex_args): Allocate stack slot for
> unassigned parms before splitting.
> (parm_in_unassigned_mem_p): New. Use it instead of
> parm_maybe_byref_p throughout this file.
> (assign_parm_setup_block): Use it. Accept pseudos in the
> expand-assigned rtl.
> (assign_parm_setup_reg): Drop BLKmode requirement.
> (assign_parm_setup_stack): Allocate and fill in the address of
> unassigned MEM parms.
> ---
> gcc/cfgexpand.c | 44 ++++++++++++++++++++++------
> gcc/cfgexpand.h | 2 +
> gcc/function.c | 74
> ++++++++++++++++++++++++++++++++++++++++-------
> gcc/tree-ssa-coalesce.c | 4 +--
> 4 files changed, 100 insertions(+), 24 deletions(-)
>
> diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
> index 0bc20f6..d567a87 100644
> --- a/gcc/cfgexpand.c
> +++ b/gcc/cfgexpand.c
> @@ -172,17 +172,23 @@ leader_merge (tree cur, tree next)
> return cur;
> }
>
> -/* Return true if VAR is a PARM_DECL or a RESULT_DECL of type BLKmode.
> +/* Return true if VAR is a PARM_DECL or a RESULT_DECL that ought to be
> + assigned to a stack slot. We can't have expand_one_ssa_partition
> + choose their address: the pseudo holding the address would be set
> + up too late for assign_params to copy the parameter if needed.
> +
> Such parameters are likely passed as a pointer to the value, rather
> than as a value, and so we must not coalesce them, nor allocate
> stack space for them before determining the calling conventions for
> - them. For their SSA_NAMEs, expand_one_ssa_partition emits RTL as
> - MEMs with pc_rtx as the address, and then it replaces the pc_rtx
> - with NULL so as to make sure the MEM is not used before it is
> - adjusted in assign_parm_setup_reg. */
> + them.
> +
> + For their SSA_NAMEs, expand_one_ssa_partition emits RTL as MEMs
> + with pc_rtx as the address, and then it replaces the pc_rtx with
> + NULL so as to make sure the MEM is not used before it is adjusted
> + in assign_parm_setup_reg. */
>
> bool
> -parm_maybe_byref_p (tree var)
> +parm_in_stack_slot_p (tree var)
> {
> if (!var || VAR_P (var))
> return false;
> @@ -190,7 +196,7 @@ parm_maybe_byref_p (tree var)
> gcc_assert (TREE_CODE (var) == PARM_DECL
> || TREE_CODE (var) == RESULT_DECL);
>
> - return TYPE_MODE (TREE_TYPE (var)) == BLKmode;
> + return !use_register_for_decl (var);
> }
>
> /* Return the partition of the default SSA_DEF for decl VAR. */
> @@ -1343,17 +1349,35 @@ expand_one_ssa_partition (tree var)
>
> if (!use_register_for_decl (var))
> {
> - if (parm_maybe_byref_p (SSA_NAME_VAR (var))
> - && ssa_default_def_partition (SSA_NAME_VAR (var)) == part)
> + /* We can't risk having the parm assigned to a MEM location
> + whose address references a pseudo, for the pseudo will only
> + be set up after arguments are copied to the stack slot.
> +
> + If the parm doesn't have a default def (e.g., because its
> + incoming value is unused), then we want to let assign_params
> + do the allocation, too. In this case we want to make sure
> + SSA_NAMEs associated with the parm don't get assigned to more
> + than one partition, lest we'd create two unassigned stac
> + slots for the same parm, thus the assert at the end of the
> + block. */
> + if (parm_in_stack_slot_p (SSA_NAME_VAR (var))
> + && (ssa_default_def_partition (SSA_NAME_VAR (var)) == part
> + || !ssa_default_def (cfun, SSA_NAME_VAR (var))))
> {
> expand_one_stack_var_at (var, pc_rtx, 0, 0);
> rtx x = SA.partition_to_pseudo[part];
> gcc_assert (GET_CODE (x) == MEM);
> - gcc_assert (GET_MODE (x) == BLKmode);
> gcc_assert (XEXP (x, 0) == pc_rtx);
> /* Reset the address, so that any attempt to use it will
> ICE. It will be adjusted in assign_parm_setup_reg. */
> XEXP (x, 0) = NULL_RTX;
> + /* If the RTL associated with the parm is not what we have
> + just created, the parm has been split over multiple
> + partitions. In order for this to work, we must have a
> + default def for the parm, otherwise assign_params won't
> + know what to do. */
> + gcc_assert (DECL_RTL_IF_SET (SSA_NAME_VAR (var)) == x
> + || ssa_default_def (cfun, SSA_NAME_VAR (var)));
> }
> else if (defer_stack_allocation (var, true))
> add_stack_var (var);
> diff --git a/gcc/cfgexpand.h b/gcc/cfgexpand.h
> index 987cf356..d168672 100644
> --- a/gcc/cfgexpand.h
> +++ b/gcc/cfgexpand.h
> @@ -22,7 +22,7 @@ along with GCC; see the file COPYING3. If not see
>
> extern tree gimple_assign_rhs_to_tree (gimple);
> extern HOST_WIDE_INT estimated_stack_frame_size (struct cgraph_node *);
> -extern bool parm_maybe_byref_p (tree);
> +extern bool parm_in_stack_slot_p (tree);
> extern rtx get_rtl_for_parm_ssa_default_def (tree var);
>
>
> diff --git a/gcc/function.c b/gcc/function.c
> index 715c19f..222c76f 100644
> --- a/gcc/function.c
> +++ b/gcc/function.c
> @@ -153,6 +153,7 @@ static void do_clobber_return_reg (rtx, void *);
> static void do_use_return_reg (rtx, void *);
> static rtx rtl_for_parm (struct assign_parm_data_all *, tree);
> static void maybe_reset_rtl_for_parm (tree);
> +static bool parm_in_unassigned_mem_p (tree, rtx);
>
>
> /* Stack of nested functions. */
> @@ -2326,6 +2327,22 @@ split_complex_args (struct assign_parm_data_all *all,
> vec<tree> *args)
> rtx rtl = rtl_for_parm (all, cparm);
> if (rtl)
> {
> + /* If this is parm is unassigned, assign it now: the
> + newly-created decls wouldn't expect the need for
> + assignment, and if they were assigned
> + independently, they might not end up in adjacent
> + slots, so unsplit wouldn't be able to fill in the
> + unassigned address of the complex MEM. */
> + if (parm_in_unassigned_mem_p (cparm, rtl))
> + {
> + int align = STACK_SLOT_ALIGNMENT
> + (TREE_TYPE (cparm), GET_MODE (rtl), MEM_ALIGN (rtl));
> + rtx loc = assign_stack_local
> + (GET_MODE (rtl), GET_MODE_SIZE (GET_MODE (rtl)),
> + align);
> + XEXP (rtl, 0) = XEXP (loc, 0);
> + }
> +
> SET_DECL_RTL (p, read_complex_part (rtl, false));
> SET_DECL_RTL (decl, read_complex_part (rtl, true));
>
> @@ -2934,6 +2951,27 @@ assign_parm_setup_block_p (struct assign_parm_data_one
> *data)
> return false;
> }
>
> +/* Return true if FROM_EXPAND is a MEM with an address to be filled in
> + by assign_params. This should be the case if, and only if,
> + parm_in_stack_slot_p holds for the parm DECL that expanded to
> + FROM_EXPAND, so we check that, too. */
> +
> +static bool
> +parm_in_unassigned_mem_p (tree decl, rtx from_expand)
> +{
> + bool result = MEM_P (from_expand) && !XEXP (from_expand, 0);
> +
> + gcc_assert (result == parm_in_stack_slot_p (decl)
> + /* Maybe it was already assigned. That's ok, especially
> + for split complex args. */
> + || (!result && MEM_P (from_expand)
> + && (XEXP (from_expand, 0) == virtual_stack_vars_rtx
> + || (GET_CODE (XEXP (from_expand, 0)) == PLUS
> + && XEXP (XEXP (from_expand, 0), 0) ==
> virtual_stack_vars_rtx))));
> +
> + return result;
> +}
> +
> /* A subroutine of assign_parms. Arrange for the parameter to be
> present and valid in DATA->STACK_RTL. */
>
> @@ -2956,8 +2994,7 @@ assign_parm_setup_block (struct assign_parm_data_all
> *all,
> {
> DECL_ALIGN (parm) = MAX (DECL_ALIGN (parm), BITS_PER_WORD);
> rtx from_expand = rtl_for_parm (all, parm);
> - if (from_expand && (!parm_maybe_byref_p (parm)
> - || XEXP (from_expand, 0) != NULL_RTX))
> + if (from_expand && !parm_in_unassigned_mem_p (parm, from_expand))
> stack_parm = copy_rtx (from_expand);
> else
> {
> @@ -2968,8 +3005,7 @@ assign_parm_setup_block (struct assign_parm_data_all
> *all,
> if (from_expand)
> {
> gcc_assert (GET_CODE (stack_parm) == MEM);
> - gcc_assert (GET_CODE (from_expand) == MEM);
> - gcc_assert (XEXP (from_expand, 0) == NULL_RTX);
> + gcc_assert (parm_in_unassigned_mem_p (parm, from_expand));
> XEXP (from_expand, 0) = XEXP (stack_parm, 0);
> PUT_MODE (from_expand, GET_MODE (stack_parm));
> stack_parm = copy_rtx (from_expand);
> @@ -3017,6 +3053,11 @@ assign_parm_setup_block (struct assign_parm_data_all
> *all,
> else if (size == 0)
> ;
>
> + /* MEM may be a REG if coalescing assigns the param's partition
> + to a pseudo. */
> + else if (REG_P (mem))
> + emit_move_insn (mem, entry_parm);
> +
> /* If SIZE is that of a mode no bigger than a word, just use
> that mode's store operation. */
> else if (size <= UNITS_PER_WORD)
> @@ -3121,7 +3162,7 @@ assign_parm_setup_reg (struct assign_parm_data_all
> *all, tree parm,
> if (GET_MODE (parmreg) != promoted_nominal_mode)
> parmreg = gen_lowpart (promoted_nominal_mode, parmreg);
> }
> - else if (!from_expand || parm_maybe_byref_p (parm))
> + else if (!from_expand || parm_in_unassigned_mem_p (parm, from_expand))
> {
> parmreg = gen_reg_rtx (promoted_nominal_mode);
> if (!DECL_ARTIFICIAL (parm))
> @@ -3131,7 +3172,6 @@ assign_parm_setup_reg (struct assign_parm_data_all
> *all, tree parm,
> {
> gcc_assert (data->passed_pointer);
> gcc_assert (GET_CODE (from_expand) == MEM
> - && GET_MODE (from_expand) == BLKmode
> && XEXP (from_expand, 0) == NULL_RTX);
> XEXP (from_expand, 0) = parmreg;
> }
> @@ -3349,7 +3389,7 @@ assign_parm_setup_reg (struct assign_parm_data_all
> *all, tree parm,
> did_conversion = true;
> }
> else if (GET_MODE (parmreg) == BLKmode)
> - gcc_assert (parm_maybe_byref_p (parm));
> + gcc_assert (parm_in_stack_slot_p (parm));
> else
> emit_move_insn (parmreg, src);
>
> @@ -3455,12 +3495,15 @@ assign_parm_setup_stack (struct assign_parm_data_all
> *all, tree parm,
> if (data->entry_parm != data->stack_parm)
> {
> rtx src, dest;
> + rtx from_expand = NULL_RTX;
>
> if (data->stack_parm == 0)
> {
> - rtx x = data->stack_parm = rtl_for_parm (all, parm);
> - if (x)
> - gcc_assert (GET_MODE (x) == GET_MODE (data->entry_parm));
> + from_expand = rtl_for_parm (all, parm);
> + if (from_expand)
> + gcc_assert (GET_MODE (from_expand) == GET_MODE
> (data->entry_parm));
> + if (from_expand && !parm_in_unassigned_mem_p (parm, from_expand))
> + data->stack_parm = from_expand;
> }
>
> if (data->stack_parm == 0)
> @@ -3472,7 +3515,16 @@ assign_parm_setup_stack (struct assign_parm_data_all
> *all, tree parm,
> = assign_stack_local (GET_MODE (data->entry_parm),
> GET_MODE_SIZE (GET_MODE (data->entry_parm)),
> align);
> - set_mem_attributes (data->stack_parm, parm, 1);
> + if (!from_expand)
> + set_mem_attributes (data->stack_parm, parm, 1);
> + else
> + {
> + gcc_assert (GET_CODE (data->stack_parm) == MEM);
> + gcc_assert (parm_in_unassigned_mem_p (parm, from_expand));
> + XEXP (from_expand, 0) = XEXP (data->stack_parm, 0);
> + PUT_MODE (from_expand, GET_MODE (data->stack_parm));
> + data->stack_parm = copy_rtx (from_expand);
> + }
> }
>
> dest = validize_mem (copy_rtx (data->stack_parm));
> diff --git a/gcc/tree-ssa-coalesce.c b/gcc/tree-ssa-coalesce.c
> index 08ce72c..6468012 100644
> --- a/gcc/tree-ssa-coalesce.c
> +++ b/gcc/tree-ssa-coalesce.c
> @@ -1386,8 +1386,8 @@ gimple_can_coalesce_p (tree name1, tree name2)
> because it may be passed by reference. */
> return ((!var1 || VAR_P (var1)) && (!var2 || VAR_P (var2)))
> || (/* The case var1 == var2 is already covered above. */
> - !parm_maybe_byref_p (var1)
> - && !parm_maybe_byref_p (var2)
> + !parm_in_stack_slot_p (var1)
> + && !parm_in_stack_slot_p (var2)
> && promote_ssa_mode (name1, NULL) == promote_ssa_mode (name2,
> NULL));
> }
>
>
>
> --
> Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
> You must be the change you wish to see in the world. -- Gandhi
> Be Free! -- http://FSFLA.org/ FSF Latin America board member
> Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer
