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| // RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern %s -emit-llvm -o - | FileCheck %s
// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero %s -emit-llvm -o - | FileCheck %s
// C guarantees that brace-init with fewer initializers than members in the
// aggregate will initialize the rest of the aggregate as-if it were static
// initialization. In turn static initialization guarantees that padding is
// initialized to zero bits.
// CHECK: @__const.partial_init.s = private unnamed_addr constant { i8, [7 x i8], i64 } { i8 42, [7 x i8] zeroinitializer, i64 0 }, align 8
// Technically, we could initialize this padding to non-zero because all of the
// struct's members have initializers.
// CHECK: @__const.init_all.s = private unnamed_addr constant { i8, [7 x i8], i64 } { i8 42, [7 x i8] zeroinitializer, i64 -2401053089374216531 }, align 8
struct S {
char c;
long long l;
};
void use(struct S*);
// CHECK-LABEL: @empty_braces(
// CHECK: %s = alloca
// CHECK-NEXT: %[[B:[0-9+]]] = bitcast %struct.S* %s to i8*
// CHECK-NEXT: call void @llvm.memset{{.*}}(i8* align 8 %[[B]], i8 0,
// CHECK-NEXT: call void @use(%struct.S* %s)
void empty_braces() {
struct S s = {};
return use(&s);
}
// CHECK-LABEL: @partial_init(
// CHECK: %s = alloca
// CHECK-NEXT: %[[B:[0-9+]]] = bitcast %struct.S* %s to i8*
// CHECK-NEXT: call void @llvm.memcpy{{.*}}(i8* align 8 %[[B]], {{.*}}@__const.partial_init.s
// CHECK-NEXT: call void @use(%struct.S* %s)
void partial_init() {
struct S s = { .c = 42 };
return use(&s);
}
// CHECK-LABEL: @init_all(
// CHECK: %s = alloca
// CHECK-NEXT: %[[B:[0-9+]]] = bitcast %struct.S* %s to i8*
// CHECK-NEXT: call void @llvm.memcpy{{.*}}(i8* align 8 %[[B]], {{.*}}@__const.init_all.s
// CHECK-NEXT: call void @use(%struct.S* %s)
void init_all() {
struct S s = { .c = 42, .l = 0xdeadbeefc0fedead };
return use(&s);
}
|