clang/test/CodeGenCXX/cxx23-assume.cpp

   1 // RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++23 %s -emit-llvm -o - | FileCheck %s
   2 // RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++23 -fno-assumptions %s -emit-llvm -o - | FileCheck %s --check-prefix=DISABLED
   3
   4 // DISABLED-NOT: @llvm.assume
   5
   6 bool f();
   7
   8 template <typename T>
   9 void f2() {
  10   [[assume(sizeof(T) == sizeof(int))]];
  11 }
  12
  13 // CHECK: @_Z1gii(i32 noundef [[X:%.*]], i32 noundef [[Y:%.*]])
  14 // CHECK-NEXT: entry:
  15 // CHECK-NEXT: [[X_ADDR:%.*]] = alloca i32
  16 // CHECK-NEXT: [[Y_ADDR:%.*]] = alloca i32
  17 // CHECK-NEXT: store i32 [[X]], ptr [[X_ADDR]]
  18 // CHECK-NEXT: store i32 [[Y]], ptr [[Y_ADDR]]
  19 void g(int x, int y) {
  20   // Not emitted because it has side-effects.
  21   [[assume(f())]];
  22
  23   // CHECK-NEXT: call void @llvm.assume(i1 true)
  24   [[assume((1, 2))]];
  25
  26   // CHECK-NEXT: [[X1:%.*]] = load i32, ptr [[X_ADDR]]
  27   // CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[X1]], 27
  28   // CHECK-NEXT: call void @llvm.assume(i1 [[CMP1]])
  29   [[assume(x != 27)]];
  30
  31   // CHECK-NEXT: [[X2:%.*]] = load i32, ptr [[X_ADDR]]
  32   // CHECK-NEXT: [[Y2:%.*]] = load i32, ptr [[Y_ADDR]]
  33   // CHECK-NEXT: [[CMP2:%.*]] = icmp eq i32 [[X2]], [[Y2]]
  34   // CHECK-NEXT: call void @llvm.assume(i1 [[CMP2]])
  35   [[assume(x == y)]];
  36
  37   // CHECK-NEXT: call void @_Z2f2IiEvv()
  38   f2<int>();
  39
  40   // CHECK-NEXT: call void @_Z2f2IdEvv()
  41   f2<double>();
  42 }
  43
  44 // CHECK: void @_Z2f2IiEvv()
  45 // CHECK-NEXT: entry:
  46 // CHECK-NEXT: call void @llvm.assume(i1 true)
  47
  48 // CHECK: void @_Z2f2IdEvv()
  49 // CHECK-NEXT: entry:
  50 // CHECK-NEXT: call void @llvm.assume(i1 false)