We need to take type alignment padding into account whe computing physical
layouts.
The layout must be compatible with the input layout, offsets are defined in
terms of offsets within a packed struct which are computed in terms of the alloc
size of a type.
Usingthe store size we would insert padding for the following type for example:
struct {
int3 v;
long long l;
} __attribute((packed))
On x86-64 int3 is padded to int4 alignment. The swiftcc type would be
<{ <3 x float>, [4 x i8], i64 }> which is not compatible with <{ <3 x float>,
i64 }>.
The latter has i64 at offset 16 and the former at offset 20.
rdar://32618125
llvm-svn: 305956
John McCall