clang/test/CodeGen/bpf-preserve-static-offset-bitfield.c

   1 // NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 2
   2 // REQUIRES: bpf-registered-target
   3 // RUN: %clang_cc1 -triple bpfel -disable-llvm-passes -emit-llvm -o - %s | FileCheck %s
   4
   5 // Check that call to preserve.static.offset is generated when bitfield
   6 // from a struct marked with __attribute__((preserve_static_offset)) is
   7 // accessed.
   8
   9 #define __ctx __attribute__((preserve_static_offset))
  10
  11 struct foo {
  12   unsigned a:1;
  13 } __ctx;
  14
  15 // CHECK-LABEL: define dso_local void @lvalue_bitfield
  16 // CHECK-SAME: (ptr noundef [[P:%.*]]) #[[ATTR0:[0-9]+]] {
  17 // CHECK-NEXT:  entry:
  18 // CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8
  19 // CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR]], align 8
  20 // CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR]], align 8
  21 // CHECK-NEXT:    [[TMP1:%.*]] = call ptr @llvm.preserve.static.offset(ptr [[TMP0]])
  22 // CHECK-NEXT:    [[BF_LOAD:%.*]] = load i8, ptr [[TMP1]], align 4
  23 // CHECK-NEXT:    [[BF_CLEAR:%.*]] = and i8 [[BF_LOAD]], -2
  24 // CHECK-NEXT:    [[BF_SET:%.*]] = or i8 [[BF_CLEAR]], 1
  25 // CHECK-NEXT:    store i8 [[BF_SET]], ptr [[TMP1]], align 4
  26 // CHECK-NEXT:    ret void
  27 //
  28 void lvalue_bitfield(struct foo *p) {
  29   p->a = 1;
  30 }