reference, declaration → definition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced

    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103

// RUN: %clang_cc1 -emit-llvm -triple %itanium_abi_triple -std=c++11 -o - %s | FileCheck --check-prefixes=CHECK,CHECK-COMMON %s
// RUN: %clang_cc1 -emit-llvm -triple %itanium_abi_triple -std=c++11 -O -o - %s | FileCheck %s --check-prefixes=CHECK-OPT,CHECK-COMMON
// RUN: %clang_cc1 -emit-llvm -triple %itanium_abi_triple -std=c++11 -fno-strict-return -o - %s | FileCheck %s --check-prefixes=CHECK-NOSTRICT,CHECK-COMMON
// RUN: %clang_cc1 -emit-llvm -triple %itanium_abi_triple -std=c++11 -fno-strict-return -Wno-return-type -o - %s | FileCheck %s --check-prefixes=CHECK-NOSTRICT,CHECK-COMMON
// RUN: %clang_cc1 -emit-llvm -triple %itanium_abi_triple -std=c++11 -fno-strict-return -O -o - %s | FileCheck %s --check-prefixes=CHECK-NOSTRICT-OPT,CHECK-COMMON

// CHECK-COMMON-LABEL: @_Z9no_return
int no_return() {
  // CHECK:      call void @llvm.trap
  // CHECK-NEXT: unreachable

  // CHECK-OPT-NOT: call void @llvm.trap
  // CHECK-OPT:     unreachable

  // -fno-strict-return should not emit trap + unreachable but it should return
  // an undefined value instead.

  // CHECK-NOSTRICT: alloca
  // CHECK-NOSTRICT-NEXT: load
  // CHECK-NOSTRICT-NEXT: ret i32
  // CHECK-NOSTRICT-NEXT: }

  // CHECK-NOSTRICT-OPT: ret i32 undef
}

enum Enum {
  A, B
};

// CHECK-COMMON-LABEL: @_Z27returnNotViableDontOptimize4Enum
int returnNotViableDontOptimize(Enum e) {
  switch (e) {
  case A: return 1;
  case B: return 2;
  }
  // Undefined behaviour optimization shouldn't be used when -fno-strict-return
  // is turned on, even if all the enum cases are covered in this function.

  // CHECK-NOSTRICT-NOT: call void @llvm.trap
  // CHECK-NOSTRICT-NOT: unreachable
}

struct Trivial {
  int x;
};

// CHECK-NOSTRICT-LABEL: @_Z7trivialv
Trivial trivial() {
  // This function returns a trivial record so -fno-strict-return should avoid
  // the undefined behaviour optimization.

  // CHECK-NOSTRICT-NOT: call void @llvm.trap
  // CHECK-NOSTRICT-NOT: unreachable
}

struct NonTrivialCopy {
  NonTrivialCopy(const NonTrivialCopy &);
};

// CHECK-NOSTRICT-LABEL: @_Z14nonTrivialCopyv
NonTrivialCopy nonTrivialCopy() {
  // CHECK-NOSTRICT-NOT: call void @llvm.trap
  // CHECK-NOSTRICT-NOT: unreachable
}

struct NonTrivialDefaultConstructor {
  int x;

  NonTrivialDefaultConstructor() { }
};

// CHECK-NOSTRICT-LABEL: @_Z28nonTrivialDefaultConstructorv
NonTrivialDefaultConstructor nonTrivialDefaultConstructor() {
  // CHECK-NOSTRICT-NOT: call void @llvm.trap
  // CHECK-NOSTRICT-NOT: unreachable
}

// Functions that return records with non-trivial destructors should always use
// the -fstrict-return optimization.

struct NonTrivialDestructor {
  ~NonTrivialDestructor();
};

// CHECK-NOSTRICT-LABEL: @_Z20nonTrivialDestructorv
NonTrivialDestructor nonTrivialDestructor() {
  // CHECK-NOSTRICT: call void @llvm.trap
  // CHECK-NOSTRICT-NEXT: unreachable
}

// The behavior for lambdas should be identical to functions.
// CHECK-COMMON-LABEL: @_Z10lambdaTestv
void lambdaTest() {
  auto lambda1 = []() -> int {
  };
  lambda1();

  // CHECK: call void @llvm.trap
  // CHECK-NEXT: unreachable

  // CHECK-NOSTRICT-NOT: call void @llvm.trap
  // CHECK-NOSTRICT-NOT: unreachable
}