On Wed, Jan 27, 2016 at 5:46 AM, H.J. Lu <hjl.to...@gmail.com> wrote:
> On Wed, Jan 27, 2016 at 1:03 AM, Marc Glisse <marc.gli...@inria.fr> wrote:
>> On Wed, 27 Jan 2016, Jakub Jelinek wrote:
>>
>>> On Wed, Jan 27, 2016 at 09:10:14AM +0100, Marc Glisse wrote:
>>>>>
>>>>> Revised:
>>>>>
>>>>> /* Returns true if TYPE is POD of one-byte or less in size for the
>>>>> purpose
>>>>> of layout and an empty class or an class with empty classes. */
>>>>>
>>>>> static bool
>>>>> is_empty_record (tree type)
>>>>> {
>>>>> if (type == error_mark_node)
>>>>> return false;
>>>>>
>>>>> if (!CLASS_TYPE_P (type))
>>>>> return false;
>>>>>
>>>>> if (CLASSTYPE_NON_LAYOUT_POD_P (type))
>>>>> return false;
>>>>>
>>>>> gcc_assert (COMPLETE_TYPE_P (type));
>>>>>
>>>>> if (CLASSTYPE_EMPTY_P (type))
>>>>> return true;
>>>>>
>>>>> if (int_size_in_bytes (type) > 1)
>>>>> return false;
>>>>
>>>>
>>>> That's completely arbitrary :-(
>>>
>>>
>>> Yeah. Because (adapted to be compilable with C):
>>> struct A1 {}; struct A2 {};
>>> struct B1 { struct A1 a; struct A2 b; }; struct B2 { struct A1 a; struct
>>> A2 b; };
>>> struct C1 { struct B1 a; struct B2 b; }; struct C2 { struct B1 a; struct
>>> B2 b; };
>>> struct D1 { struct C1 a; struct C2 b; }; struct D2 { struct C1 a; struct
>>> C2 b; };
>>> struct E1 { struct D1 a; struct D2 b; }; struct E2 { struct D1 a; struct
>>> D2 b; };
>>> struct F1 { struct E1 a; struct E2 b; }; struct F2 { struct E1 a; struct
>>> E2 b; };
>>> struct G1 { struct F1 a; struct F2 b; }; struct G2 { struct F1 a; struct
>>> F2 b; };
>>> struct H1 { struct G1 a; struct G2 b; }; struct H2 { struct G1 a; struct
>>> G2 b; };
>>> struct I1 { struct H1 a; struct H2 b; }; struct I2 { struct H1 a; struct
>>> H2 b; };
>>> struct J1 { struct I1 a; struct I2 b; }; struct J2 { struct I1 a; struct
>>> I2 b; };
>>> struct K1 { struct J1 a; struct J2 b; };
>>> int v;
>>> __attribute__((noinline, noclone))
>>> struct K1 foo (int a, struct K1 x, int b)
>>> {
>>> v = a + b;
>>> return x;
>>> }
>>> struct K1 k, m;
>>> void
>>> bar (void)
>>> {
>>> m = foo (1, k, 2);
>>> }
>>> then would have a different calling convention between C and C++,
>>> so where is the argument that we change anything just to make the two
>>> compatible? Though, of course, those two will never be compatible,
>>> it is enough to add struct L1 { int a; struct K1 b; int c; }; and
>>> that structure has 1024+8 bytes in C++ and 8 bytes in C.
>>
>>
>> I don't know how empty classes are used in C in practice, but it could make
>> sense to have ABI compatibility as long as no empty struct is used as a
>> member of another struct (I also suggested an attribute to let C++ use the
>> same layout as C here: PR63579). But then the usual definition of empty
>> would be sufficient.
>>
>>> As clang generates different code for the above between C and C++, it
>>> clearly special cases for some reason just the most common case.
>>> IMHO it is not worth to change GCC ABI...
>>
>>
>> I was interested in this change because it improves C++, C compatibility was
>> a convenient excuse ;-)
>>
>
> I opened a clang bug:
>
> https://llvm.org/bugs/show_bug.cgi?id=26337
>
> I propose the following definitions:
>
> i. An empty record is:
> 1. A class without member. Or
> 2. An array of empty records. Or
> 3. A class with empty records.
> ii. An empty record type for parameter passing is POD for the purpose of
> layout
> and
> 1. A class without member. Or
> 2. A class with empty records.
>
> /* An empty record is:
> 1. A class without member. Or
> 2. An array of empty records. Or
> 3. A class with empty records. */
>
> /* Returns true if TYPE is an empty record or an array of empty records. */
>
> static bool
> is_empty_record_or_array_of_empty_record (tree type)
> {
> if (CLASS_TYPE_P (type))
> {
> if (CLASSTYPE_EMPTY_P (type))
> return true;
>
> tree field;
>
> for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
> if (TREE_CODE (field) == FIELD_DECL
> && !DECL_ARTIFICIAL (field)
> && !is_empty_record_or_array_of_empty_record (TREE_TYPE (field)))
> return false;
> return true;
> }
> else if (TREE_CODE (type) == ARRAY_TYPE)
> return is_empty_record_or_array_of_empty_record (TREE_TYPE (type));
> return false;
> }
>
> /* Returns true if TYPE is POD for the purpose of layout and
> 1. A class without member. Or
> 2. A class with empty records. */
>
> static bool
> is_empty_record_for_parm (tree type)
> {
> if (type == error_mark_node)
> return false;
>
> if (!CLASS_TYPE_P (type))
> return false;
>
> if (CLASSTYPE_NON_LAYOUT_POD_P (type))
> return false;
>
> gcc_assert (COMPLETE_TYPE_P (type));
>
> if (CLASSTYPE_EMPTY_P (type))
> return true;
>
> tree field;
>
> for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
> if (TREE_CODE (field) == FIELD_DECL
> && !DECL_ARTIFICIAL (field)
> && !is_empty_record_or_array_of_empty_record (TREE_TYPE (field)))
> return false;
>
> return true;
> }
>
Here is the updated patch with new testcases. OK for trunk?
--
H.J.
From 9a3aacb5b95b317a10e65b4ed80d3f490660b171 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.to...@gmail.com>
Date: Wed, 9 Dec 2015 12:48:07 -0800
Subject: [PATCH] Properly pass C++ empty class
Use 0 for empty record size in TARGET_GIMPLIFY_VA_ARG_EXPR.
PR c++/60336
PR middle-end/67239
PR target/68355
* config/aarch64/aarch64.c (aarch64_gimplify_va_arg_expr): Use 0
for empty record size.
* config/mep/mep.c (mep_gimplify_va_arg_expr): Likewise.
* config/mips/mips.c (mips_std_gimplify_va_arg_expr): Likewise.
(mips_gimplify_va_arg_expr): Likewise.
* config/msp430/msp430.c (msp430_gimplify_va_arg_expr): Likewise.
* config/pa/pa.c (hppa_gimplify_va_arg_expr): Likewise.
* config/rs6000/rs6000.c (rs6000_gimplify_va_arg): Likewise.
* config/s390/s390.c (s390_gimplify_va_arg): Likewise.
* config/sh/sh.c (sh_gimplify_va_arg_expr): Likewise.
* config/sparc/sparc.c (sparc_gimplify_va_arg): Likewise.
* config/spu/spu.c (spu_gimplify_va_arg_expr): Likewise.
* config/stormy16/stormy16.c (xstormy16_gimplify_va_arg_expr):
Likewise.
* config/visium/visium.c (visium_gimplify_va_arg): Likewise.
* config/xtensa/xtensa.c (xtensa_gimplify_va_arg_expr): Likewise.
* config/alpha/alpha.c (alpha_setup_incoming_varargs): Replace
targetm.calls.function_arg_advance with function_arg_advance.
(alpha_gimplify_va_arg_1): Use 0 for empty record size.
* config/microblaze/microblaze.c (microblaze_expand_prologue):
Replace targetm.calls.function_arg with function_arg. Replace
targetm.calls.function_arg_advance with function_arg_advance.
* config/tilegx/tilegx.c (tilegx_setup_incoming_varargs): Replace
targetm.calls.function_arg_advance with function_arg_advance.
(tilegx_gimplify_va_arg_expr): Use 0 for empty record size.
* config/tilepro/tilepro.c (tilepro_setup_incoming_varargs):
Replace targetm.calls.function_arg_advance with
function_arg_advance.
(tilepro_gimplify_va_arg_expr): Use 0 for empty record size.
---
gcc/config/aarch64/aarch64.c | 3 ++-
gcc/config/alpha/alpha.c | 6 +++---
gcc/config/mep/mep.c | 3 ++-
gcc/config/microblaze/microblaze.c | 11 +++++------
gcc/config/mips/mips.c | 6 ++++--
gcc/config/msp430/msp430.c | 3 ++-
gcc/config/pa/pa.c | 3 ++-
gcc/config/rs6000/rs6000.c | 3 ++-
gcc/config/s390/s390.c | 3 ++-
gcc/config/sh/sh.c | 3 ++-
gcc/config/sparc/sparc.c | 3 ++-
gcc/config/spu/spu.c | 3 ++-
gcc/config/stormy16/stormy16.c | 6 ++++--
gcc/config/tilegx/tilegx.c | 7 ++++---
gcc/config/tilepro/tilepro.c | 7 ++++---
gcc/config/visium/visium.c | 3 ++-
gcc/config/xtensa/xtensa.c | 3 ++-
17 files changed, 46 insertions(+), 30 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index df3dec0..43fd394 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -9605,7 +9605,8 @@ aarch64_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
stack = build3 (COMPONENT_REF, TREE_TYPE (f_stack), unshare_expr (valist),
f_stack, NULL_TREE);
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
align = aarch64_function_arg_alignment (mode, type) / BITS_PER_UNIT;
dw_align = false;
diff --git a/gcc/config/alpha/alpha.c b/gcc/config/alpha/alpha.c
index e023d3b..c3c0513 100644
--- a/gcc/config/alpha/alpha.c
+++ b/gcc/config/alpha/alpha.c
@@ -6117,8 +6117,7 @@ alpha_setup_incoming_varargs (cumulative_args_t pcum, machine_mode mode,
CUMULATIVE_ARGS cum = *get_cumulative_args (pcum);
/* Skip the current argument. */
- targetm.calls.function_arg_advance (pack_cumulative_args (&cum), mode, type,
- true);
+ function_arg_advance (pack_cumulative_args (&cum), mode, type, true);
#if TARGET_ABI_OPEN_VMS
/* For VMS, we allocate space for all 6 arg registers plus a count.
@@ -6304,7 +6303,8 @@ alpha_gimplify_va_arg_1 (tree type, tree base, tree offset,
gimple_seq_add_seq (pre_p, internal_post);
/* Update the offset field. */
- type_size = TYPE_SIZE_UNIT (TYPE_MAIN_VARIANT (type));
+ bool empty_record = type && type_is_empty_record_p (type);
+ type_size = empty_record ? 0 : TYPE_SIZE_UNIT (TYPE_MAIN_VARIANT (type));
if (type_size == NULL || TREE_OVERFLOW (type_size))
t = size_zero_node;
else
diff --git a/gcc/config/mep/mep.c b/gcc/config/mep/mep.c
index 9c4cd86..f63ad57 100644
--- a/gcc/config/mep/mep.c
+++ b/gcc/config/mep/mep.c
@@ -3525,7 +3525,8 @@ mep_gimplify_va_arg_expr (tree valist, tree type,
ivc2_vec = TARGET_IVC2 && VECTOR_TYPE_P (type);
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
by_reference = (size > (ivc2_vec ? 8 : 4)) || (size <= 0);
if (by_reference)
diff --git a/gcc/config/microblaze/microblaze.c b/gcc/config/microblaze/microblaze.c
index baff67a..e144ff1 100644
--- a/gcc/config/microblaze/microblaze.c
+++ b/gcc/config/microblaze/microblaze.c
@@ -2798,8 +2798,8 @@ microblaze_expand_prologue (void)
passed_mode = Pmode;
}
- entry_parm = targetm.calls.function_arg (args_so_far, passed_mode,
- passed_type, true);
+ entry_parm = function_arg (args_so_far, passed_mode, passed_type,
+ true);
if (entry_parm)
{
@@ -2819,8 +2819,7 @@ microblaze_expand_prologue (void)
break;
}
- targetm.calls.function_arg_advance (args_so_far, passed_mode,
- passed_type, true);
+ function_arg_advance (args_so_far, passed_mode, passed_type, true);
next_arg = TREE_CHAIN (cur_arg);
if (next_arg == 0)
@@ -2834,8 +2833,8 @@ microblaze_expand_prologue (void)
/* Split parallel insn into a sequence of insns. */
- next_arg_reg = targetm.calls.function_arg (args_so_far, VOIDmode,
- void_type_node, true);
+ next_arg_reg = function_arg (args_so_far, VOIDmode, void_type_node,
+ true);
if (next_arg_reg != 0 && GET_CODE (next_arg_reg) == PARALLEL)
{
rtvec adjust = XVEC (next_arg_reg, 0);
diff --git a/gcc/config/mips/mips.c b/gcc/config/mips/mips.c
index 890e947..d9d0c59 100644
--- a/gcc/config/mips/mips.c
+++ b/gcc/config/mips/mips.c
@@ -6308,7 +6308,8 @@ mips_std_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
}
/* Compute the rounded size of the type. */
- type_size = size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ type_size = empty_record ? 0 : size_in_bytes (type);
rounded_size = round_up (type_size, align);
/* Reduce rounded_size so it's sharable with the postqueue. */
@@ -6397,7 +6398,8 @@ mips_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
ovfl = build3 (COMPONENT_REF, TREE_TYPE (f_ovfl), valist, f_ovfl,
NULL_TREE);
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
if (GET_MODE_CLASS (TYPE_MODE (type)) == MODE_FLOAT
&& GET_MODE_SIZE (TYPE_MODE (type)) <= UNITS_PER_FPVALUE)
diff --git a/gcc/config/msp430/msp430.c b/gcc/config/msp430/msp430.c
index 182ca59..6b1d5ca 100644
--- a/gcc/config/msp430/msp430.c
+++ b/gcc/config/msp430/msp430.c
@@ -1451,7 +1451,8 @@ msp430_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
}
/* Compute the rounded size of the type. */
- type_size = size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ type_size = empty_record ? 0 : size_in_bytes (type);
rounded_size = round_up (type_size, align);
/* Reduce rounded_size so it's sharable with the postqueue. */
diff --git a/gcc/config/pa/pa.c b/gcc/config/pa/pa.c
index 8b1c832..104dc88 100644
--- a/gcc/config/pa/pa.c
+++ b/gcc/config/pa/pa.c
@@ -6342,7 +6342,8 @@ hppa_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
type = ptr;
ptr = build_pointer_type (type);
}
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
valist_type = TREE_TYPE (valist);
/* Args grow down. Not handled by generic routines. */
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 7b9201a..bca478a 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -12074,7 +12074,8 @@ rs6000_gimplify_va_arg (tree valist, tree type, gimple_seq *pre_p,
sav = build3 (COMPONENT_REF, TREE_TYPE (f_sav), unshare_expr (valist),
f_sav, NULL_TREE);
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
rsize = (size + 3) / 4;
align = 1;
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 3be64de..b2de2f0 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -11630,7 +11630,8 @@ s390_gimplify_va_arg (tree valist, tree type, gimple_seq *pre_p,
valist = unshare_expr (valist);
ovf = build3 (COMPONENT_REF, TREE_TYPE (f_ovf), valist, f_ovf, NULL_TREE);
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
s390_check_type_for_vector_abi (type, true, false);
diff --git a/gcc/config/sh/sh.c b/gcc/config/sh/sh.c
index 0b18ce5..3977f12 100644
--- a/gcc/config/sh/sh.c
+++ b/gcc/config/sh/sh.c
@@ -8765,7 +8765,8 @@ sh_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
if (pass_by_ref)
type = build_pointer_type (type);
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
rsize = (size + UNITS_PER_WORD - 1) & -UNITS_PER_WORD;
pptr_type_node = build_pointer_type (ptr_type_node);
diff --git a/gcc/config/sparc/sparc.c b/gcc/config/sparc/sparc.c
index 71609f2..3dae250 100644
--- a/gcc/config/sparc/sparc.c
+++ b/gcc/config/sparc/sparc.c
@@ -7412,7 +7412,8 @@ sparc_gimplify_va_arg (tree valist, tree type, gimple_seq *pre_p,
else
{
indirect = false;
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
rsize = ROUND_UP (size, UNITS_PER_WORD);
align = 0;
diff --git a/gcc/config/spu/spu.c b/gcc/config/spu/spu.c
index 401c295..cafcd86 100644
--- a/gcc/config/spu/spu.c
+++ b/gcc/config/spu/spu.c
@@ -4028,7 +4028,8 @@ spu_gimplify_va_arg_expr (tree valist, tree type, gimple_seq * pre_p,
false);
if (pass_by_reference_p)
type = build_pointer_type (type);
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
rsize = ((size + UNITS_PER_WORD - 1) / UNITS_PER_WORD) * UNITS_PER_WORD;
/* build conditional expression to calculate addr. The expression
diff --git a/gcc/config/stormy16/stormy16.c b/gcc/config/stormy16/stormy16.c
index 50af15b..631bb63 100644
--- a/gcc/config/stormy16/stormy16.c
+++ b/gcc/config/stormy16/stormy16.c
@@ -1337,8 +1337,10 @@ xstormy16_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
count = build3 (COMPONENT_REF, TREE_TYPE (f_count), valist, f_count,
NULL_TREE);
+ bool empty_record = type && type_is_empty_record_p (type);
must_stack = targetm.calls.must_pass_in_stack (TYPE_MODE (type), type);
- size_tree = round_up (size_in_bytes (type), UNITS_PER_WORD);
+ size_tree = round_up (empty_record ? integer_zero_node : size_in_bytes (type),
+ UNITS_PER_WORD);
gimplify_expr (&size_tree, pre_p, NULL, is_gimple_val, fb_rvalue);
size_of_reg_args = NUM_ARGUMENT_REGISTERS * UNITS_PER_WORD;
@@ -1374,7 +1376,7 @@ xstormy16_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
/* Arguments larger than a word might need to skip over some
registers, since arguments are either passed entirely in
registers or entirely on the stack. */
- size = PUSH_ROUNDING (int_size_in_bytes (type));
+ size = PUSH_ROUNDING (empty_record ? 0 : int_size_in_bytes (type));
if (size > 2 || size < 0 || must_stack)
{
tree r, u;
diff --git a/gcc/config/tilegx/tilegx.c b/gcc/config/tilegx/tilegx.c
index 06c832c..3c7fe2b 100644
--- a/gcc/config/tilegx/tilegx.c
+++ b/gcc/config/tilegx/tilegx.c
@@ -396,8 +396,8 @@ tilegx_setup_incoming_varargs (cumulative_args_t cum,
/* The caller has advanced CUM up to, but not beyond, the last named
argument. Advance a local copy of CUM past the last "real" named
argument, to find out how many registers are left over. */
- targetm.calls.function_arg_advance (pack_cumulative_args (&local_cum),
- mode, type, true);
+ function_arg_advance (pack_cumulative_args (&local_cum), mode, type,
+ true);
first_reg = local_cum;
if (local_cum < TILEGX_NUM_ARG_REGS)
@@ -473,7 +473,8 @@ tilegx_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
if (pass_by_reference_p)
type = build_pointer_type (type);
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
rsize = ((size + UNITS_PER_WORD - 1) / UNITS_PER_WORD) * UNITS_PER_WORD;
/* If the alignment of the type is greater than the default for a
diff --git a/gcc/config/tilepro/tilepro.c b/gcc/config/tilepro/tilepro.c
index 628cd04..d1d00cf 100644
--- a/gcc/config/tilepro/tilepro.c
+++ b/gcc/config/tilepro/tilepro.c
@@ -348,8 +348,8 @@ tilepro_setup_incoming_varargs (cumulative_args_t cum,
/* The caller has advanced CUM up to, but not beyond, the last named
argument. Advance a local copy of CUM past the last "real" named
argument, to find out how many registers are left over. */
- targetm.calls.function_arg_advance (pack_cumulative_args (&local_cum),
- mode, type, true);
+ function_arg_advance (pack_cumulative_args (&local_cum), mode, type,
+ true);
first_reg = local_cum;
if (local_cum < TILEPRO_NUM_ARG_REGS)
@@ -421,7 +421,8 @@ tilepro_gimplify_va_arg_expr (tree valist, tree type, gimple_seq * pre_p,
if (pass_by_reference_p)
type = build_pointer_type (type);
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
rsize = ((size + UNITS_PER_WORD - 1) / UNITS_PER_WORD) * UNITS_PER_WORD;
/* If the alignment of the type is greater than the default for a
diff --git a/gcc/config/visium/visium.c b/gcc/config/visium/visium.c
index 7881b0e..d225a6d 100644
--- a/gcc/config/visium/visium.c
+++ b/gcc/config/visium/visium.c
@@ -1529,7 +1529,8 @@ visium_gimplify_va_arg (tree valist, tree type, gimple_seq *pre_p,
return build_va_arg_indirect_ref (t);
}
- size = int_size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ size = empty_record ? 0 : int_size_in_bytes (type);
rsize = (size + UNITS_PER_WORD - 1) & -UNITS_PER_WORD;
f_ovfl = TYPE_FIELDS (va_list_type_node);
f_gbase = TREE_CHAIN (f_ovfl);
diff --git a/gcc/config/xtensa/xtensa.c b/gcc/config/xtensa/xtensa.c
index 64d089b..a725a8b 100644
--- a/gcc/config/xtensa/xtensa.c
+++ b/gcc/config/xtensa/xtensa.c
@@ -3161,7 +3161,8 @@ xtensa_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
ndx = build3 (COMPONENT_REF, TREE_TYPE (f_ndx), unshare_expr (valist),
f_ndx, NULL_TREE);
- type_size = size_in_bytes (type);
+ bool empty_record = type && type_is_empty_record_p (type);
+ type_size = empty_record ? 0 : size_in_bytes (type);
va_size = round_up (type_size, UNITS_PER_WORD);
gimplify_expr (&va_size, pre_p, NULL, is_gimple_val, fb_rvalue);
--
2.5.0
