test/CodeGen/glibc_ptr_align.c

// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 5
// RUN: %clang_cc1 -triple=x86_64-unknown-unknown -O3 -o - -emit-llvm %s | FileCheck %s

// Make sure that we do not set inbounds flag if the base pointer may be a constant null.

// CHECK-LABEL: define dso_local ptr @glibc_ptr_align(
// CHECK-SAME: ptr noundef readnone captures(none) [[BASE:%.*]], ptr noundef [[POINTER:%.*]], i64 noundef [[ALIGN_MASK:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
// CHECK-NEXT:  [[ENTRY:.*:]]
// CHECK-NEXT:    [[SUB_PTR_LHS_CAST:%.*]] = ptrtoint ptr [[POINTER]] to i64
// CHECK-NEXT:    [[ADD:%.*]] = add nsw i64 [[ALIGN_MASK]], [[SUB_PTR_LHS_CAST]]
// CHECK-NEXT:    [[NOT:%.*]] = xor i64 [[ALIGN_MASK]], -1
// CHECK-NEXT:    [[AND:%.*]] = and i64 [[ADD]], [[NOT]]
// CHECK-NEXT:    [[TMP0:%.*]] = inttoptr i64 [[AND]] to ptr
// CHECK-NEXT:    ret ptr [[TMP0]]
//
char *glibc_ptr_align(char *base, char *pointer, long align_mask) {
  return (sizeof(long int) < sizeof(void *) ? (base) : (char *)0) +
         (((pointer) -
           (sizeof(long int) < sizeof(void *) ? (base) : (char *)0) +
           (align_mask)) &
          ~(align_mask));
}

// CHECK-LABEL: define dso_local ptr @glibc_ptr_align_commuted(
// CHECK-SAME: ptr noundef readnone captures(none) [[BASE:%.*]], ptr noundef [[POINTER:%.*]], i64 noundef [[ALIGN_MASK:%.*]]) local_unnamed_addr #[[ATTR0]] {
// CHECK-NEXT:  [[ENTRY:.*:]]
// CHECK-NEXT:    [[SUB_PTR_LHS_CAST:%.*]] = ptrtoint ptr [[POINTER]] to i64
// CHECK-NEXT:    [[ADD:%.*]] = add nsw i64 [[ALIGN_MASK]], [[SUB_PTR_LHS_CAST]]
// CHECK-NEXT:    [[NOT:%.*]] = xor i64 [[ALIGN_MASK]], -1
// CHECK-NEXT:    [[AND:%.*]] = and i64 [[ADD]], [[NOT]]
// CHECK-NEXT:    [[TMP0:%.*]] = inttoptr i64 [[AND]] to ptr
// CHECK-NEXT:    ret ptr [[TMP0]]
//
char *glibc_ptr_align_commuted(char *base, char *pointer, long align_mask) {
  return (sizeof(long int) >= sizeof(void *) ? (char *)0 : (base)) +
         (((pointer) -
           (sizeof(long int) >= sizeof(void *) ? (char *)0 : (base)) +
           (align_mask)) &
          ~(align_mask));
}

// CHECK-LABEL: define dso_local ptr @glibc_ptr_align_non_constexpr(
// CHECK-SAME: ptr noundef [[BASE:%.*]], ptr noundef [[POINTER:%.*]], i64 noundef [[ALIGN_MASK:%.*]], i32 noundef [[COND:%.*]]) local_unnamed_addr #[[ATTR0]] {
// CHECK-NEXT:  [[ENTRY:.*:]]
// CHECK-NEXT:    [[TOBOOL_NOT:%.*]] = icmp eq i32 [[COND]], 0
// CHECK-NEXT:    [[COND1:%.*]] = select i1 [[TOBOOL_NOT]], ptr null, ptr [[BASE]]
// CHECK-NEXT:    [[SUB_PTR_LHS_CAST:%.*]] = ptrtoint ptr [[POINTER]] to i64
// CHECK-NEXT:    [[SUB_PTR_RHS_CAST:%.*]] = ptrtoint ptr [[COND1]] to i64
// CHECK-NEXT:    [[SUB_PTR_SUB:%.*]] = add i64 [[ALIGN_MASK]], [[SUB_PTR_LHS_CAST]]
// CHECK-NEXT:    [[ADD:%.*]] = sub i64 [[SUB_PTR_SUB]], [[SUB_PTR_RHS_CAST]]
// CHECK-NEXT:    [[NOT:%.*]] = xor i64 [[ALIGN_MASK]], -1
// CHECK-NEXT:    [[AND:%.*]] = and i64 [[ADD]], [[NOT]]
// CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, ptr [[COND1]], i64 [[AND]]
// CHECK-NEXT:    ret ptr [[ADD_PTR]]
//
char *glibc_ptr_align_non_constexpr(char *base, char *pointer, long align_mask, int cond) {
  return (cond ? (base) : (char *)0) +
         (((pointer) -
           (cond ? (base) : (char *)0) +
           (align_mask)) &
          ~(align_mask));
}