clang/test/C/drs/dr335.c

   1 /* RUN: %clang_cc1 -std=c89 -triple x86_64-pc-win32 -emit-llvm -o - %s | FileCheck %s
   2    RUN: %clang_cc1 -std=c89 -triple i686-pc-linux -emit-llvm -o - %s | FileCheck %s
   3    RUN: %clang_cc1 -std=c99 -triple x86_64-pc-win32 -emit-llvm -o - %s | FileCheck %s
   4    RUN: %clang_cc1 -std=c99 -triple i686-pc-linux -emit-llvm -o - %s | FileCheck %s
   5    RUN: %clang_cc1 -std=c11 -triple x86_64-pc-win32 -emit-llvm -o - %s | FileCheck %s
   6    RUN: %clang_cc1 -std=c11 -triple i686-pc-linux -emit-llvm -o - %s | FileCheck %s
   7    RUN: %clang_cc1 -std=c17 -triple x86_64-pc-win32 -emit-llvm -o - %s | FileCheck %s
   8    RUN: %clang_cc1 -std=c17 -triple i686-pc-linux -emit-llvm -o - %s | FileCheck %s
   9    RUN: %clang_cc1 -std=c2x -triple x86_64-pc-win32 -emit-llvm -o - %s | FileCheck %s
  10    RUN: %clang_cc1 -std=c2x -triple i686-pc-linux -emit-llvm -o - %s | FileCheck %s
  11  */
  12
  13 /* WG14 DR335: yes
  14  * _Bool bit-fields
  15  *
  16  * This validates the runtime behavior from the DR, see dr3xx.c for the compile
  17  * time enforcement portion.
  18  */
  19 void dr335(void) {
  20   struct bits_ {
  21     _Bool bbf1 : 1;
  22   } bits = { 1 };
  23
  24   bits.bbf1 = ~bits.bbf1;
  25
  26   // First, load the value from bits.bbf1 and truncate it down to one-bit.
  27
  28   // CHECK: %[[LOAD1:.+]] = load i8, ptr {{.+}}, align 1
  29   // CHECK-NEXT: %[[CLEAR1:.+]] = and i8 %[[LOAD1]], 1
  30   // CHECK-NEXT: %[[CAST:.+]] = trunc i8 %[[CLEAR1]] to i1
  31   // CHECK-NEXT: %[[CONV:.+]] = zext i1 %[[CAST]] to i32
  32
  33   // Second, perform the unary complement.
  34
  35   // CHECK-NEXT: %[[NOT:.+]] = xor i32 %[[CONV]], -1
  36
  37   // Finally, test the new value against 0. If it's nonzero, then assign one
  38   // into the bit-field, otherwise assign zero into the bit-field. Note, this
  39   // does not perform the operation on the promoted value, so this matches the
  40   // requirements in C99 6.3.1.2, so a bit-field of type _Bool behaves like a
  41   // _Bool and not like an [unsigned] int.
  42   // CHECK-NEXT: %[[TOBOOL:.+]] = icmp ne i32 %[[NOT]], 0
  43   // CHECK-NEXT: %[[ZERO:.+]] = zext i1 %[[TOBOOL]] to i8
  44   // CHECK-NEXT: %[[LOAD2:.+]] = load i8, ptr {{.+}}, align 1
  45   // CHECK-NEXT: %[[CLEAR2:.+]] = and i8 %[[LOAD2]], -2
  46   // CHECK-NEXT: %[[SET:.+]] = or i8 %[[CLEAR2]], %[[ZERO]]
  47   // CHECK-NEXT: store i8 %[[SET]], ptr {{.+}}, align 1
  48   // CHECK-NEXT: {{.+}} = trunc i8 %[[ZERO]] to i1
  49 }
  50