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