On Aug 16, 2015, Andreas Schwab <sch...@linux-m68k.org> wrote:
> On m68k:
> FAIL: gcc.c-torture/execute/20050316-1.c -O0 execution test
> FAIL: gcc.c-torture/execute/20050316-2.c -O0 execution test
> FAIL: gcc.c-torture/execute/20050316-3.c -O0 execution test
> FAIL: gcc.c-torture/execute/simd-4.c -O0 execution test
> FAIL: gcc.c-torture/execute/simd-6.c -O0 execution test
> FAIL: gcc.dg/compat/vector-1 c_compat_x_tst.o-c_compat_y_tst.o execute
Thanks. Interesting. This exposes a more general situation than the
one I covered with the byref params: the general case does not require
the params to be passed by reference, but rather that the params require
a stack address that, if determined by cfgexpand, will cause them to be
computed too late for assign_parms' use. The following patch appears to
fix the problem, applying the same logic of limited coalescing and
deferred address assignment to all params that can't live in pseudos,
and extending assign_parms' remaining case of copying incoming params to
new stack slots to fill in the blank address with that of the
newly-allocated stack slot.
Would you be so kind as to give it a spin on a m68k native? TIA,
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 0bc20f6..56571ce 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. */
@@ -1343,13 +1349,15 @@ expand_one_ssa_partition (tree var)
if (!use_register_for_decl (var))
{
- if (parm_maybe_byref_p (SSA_NAME_VAR (var))
+ /* 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 (parm_in_stack_slot_p (SSA_NAME_VAR (var))
&& ssa_default_def_partition (SSA_NAME_VAR (var)) == part)
{
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. */
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..eccd8c6 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -2934,6 +2934,16 @@ assign_parm_setup_block_p (struct assign_parm_data_one
*data)
return false;
}
+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));
+
+ return result;
+}
+
/* A subroutine of assign_parms. Arrange for the parameter to be
present and valid in DATA->STACK_RTL. */
@@ -2956,8 +2966,7 @@ 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 +2977,7 @@ 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);
@@ -3121,7 +3129,7 @@ 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))
@@ -3349,7 +3357,7 @@ 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 +3463,15 @@ 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));
+ else if (!parm_in_unassigned_mem_p (parm, from_expand))
+ data->stack_parm = from_expand;
}
if (data->stack_parm == 0)
@@ -3472,7 +3483,16 @@ 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
