[X86_64] fix arg pass error in struct. (#86902)

```
typedef long long t67 __attribute__((aligned (4)));
struct s67 {
  int a;
  t67 b;
};
void f67(struct s67 x) {
}
```
When classify:
a: Lo = Integer, Hi = NoClass
b: Lo = Integer, Hi = NoClass
struct S: Lo = Integer, Hi = NoClass

```
define dso_local void @F67(i64 %x.coerce) {
```
In this case, only one i64 register is used when the structure parameter
is transferred, which is obviously incorrect.So we need to treat the
split case specially. fix
#85387.

Author: CoTinker

clang/lib/CodeGen/Targets/X86.cpp

@@ -2106,8 +2106,11 @@ void X86_64ABIInfo::classify(QualType Ty, uint64_t OffsetBase, Class &Lo,
         postMerge(Size, Lo, Hi);
         return;
       }
+
+      bool IsInMemory =
+          Offset % getContext().getTypeAlign(i->getType().getCanonicalType());
       // Note, skip this test for bit-fields, see below.
-      if (!BitField && Offset % getContext().getTypeAlign(i->getType())) {
+      if (!BitField && IsInMemory) {
         Lo = Memory;
         postMerge(Size, Lo, Hi);
         return;

clang/test/CodeGen/X86/x86_64-arguments.c

@@ -533,6 +533,24 @@ typedef float t66 __attribute__((__vector_size__(128), __aligned__(128)));
 void f66(t66 a0) {
 }
 
+typedef long long t67 __attribute__((aligned (4)));
+struct s67 {
+  int a;
+  t67 b;
+};
+// CHECK-LABEL: define{{.*}} void @f67(ptr noundef byval(%struct.s67) align 8 %x)
+void f67(struct s67 x) {
+}
+
+typedef double t68 __attribute__((aligned (4)));
+struct s68 {
+  int a;
+  t68 b;
+};
+// CHECK-LABEL: define{{.*}} void @f68(ptr noundef byval(%struct.s68) align 8 %x)
+void f68(struct s68 x) {
+}
+
 /// The synthesized __va_list_tag does not have file/line fields.
 // CHECK:      = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "__va_list_tag",
 // CHECK-NOT:  file: