https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65146
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org,
| |uros at gcc dot gnu.org
--- Comment #21 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, are we talking about something like (no -Wpsabi here)
--- gcc/config/i386/i386.c.jj 2020-08-24 10:00:01.321258451 +0200
+++ gcc/config/i386/i386.c 2020-08-26 17:54:39.089468108 +0200
@@ -16487,7 +16487,11 @@ iamcu_alignment (tree type, int align)
/* Intel MCU psABI specifies scalar types > 4 bytes aligned to 4
bytes. */
- mode = TYPE_MODE (strip_array_types (type));
+ type = strip_array_types (type);
+ if (TYPE_ATOMIC (type))
+ return align;
+
+ mode = TYPE_MODE (type);
switch (GET_MODE_CLASS (mode))
{
case MODE_INT:
@@ -16757,7 +16761,7 @@ ix86_minimum_alignment (tree exp, machin
/* Don't do dynamic stack realignment for long long objects with
-mpreferred-stack-boundary=2. */
if ((mode == DImode || (type && TYPE_MODE (type) == DImode))
- && (!type || !TYPE_USER_ALIGN (type))
+ && (!type || (!TYPE_USER_ALIGN (type) && !TYPE_ATOMIC (type)))
&& (!decl || !DECL_USER_ALIGN (decl)))
{
gcc_checking_assert (!TARGET_STV);
@@ -20293,7 +20297,10 @@ x86_field_alignment (tree type, int comp
return computed;
if (TARGET_IAMCU)
return iamcu_alignment (type, computed);
- mode = TYPE_MODE (strip_array_types (type));
+ type = strip_array_types (type);
+ if (TYPE_ATOMIC (type))
+ return computed;
+ mode = TYPE_MODE (type);
if (mode == DFmode || mode == DCmode
|| GET_MODE_CLASS (mode) == MODE_INT
|| GET_MODE_CLASS (mode) == MODE_COMPLEX_INT)
No idea whether we need the ix86_minimum_alignment change and about IAMCU I'll
defer to H.J., but the last hunk fixes something like #c1 or
struct A { char a; _Atomic long long b; };
struct B { char a; _Atomic double b; };
int a = __builtin_offsetof (struct A, b);
int b = __builtin_offsetof (struct B, b);
with -m32 for me.
