clang/test/CodeGenCXX/cxx20-decomposition.cpp

   1 // RUN: %clang_cc1 -std=c++20 -triple x86_64-linux-gnu -emit-llvm %s -o - | FileCheck %s
   2
   3 struct S {
   4   int i;
   5   int j;
   6 };
   7
   8 int f() {
   9   auto [i, j] = S{1, 42};
  10   return [&i, j] {
  11     return i + j;
  12   }();
  13 }
  14
  15 // Ensures the representation of the lambda, the order of the
  16 // 1st 2nd don't matter except for ABI-esque things, but make sure
  17 // that the ref-capture is a ptr, and 'j' is captured by value.
  18 // CHECK: %[[LAMBDA_TY:.+]] = type <{ ptr, i32, [4 x i8] }>
  19
  20 // Check the captures themselves.
  21 // CHECK: define{{.*}} i32 @_Z1fv()
  22 // CHECK: %[[BINDING:.+]] = alloca %struct.S
  23 // CHECK: %[[LAMBDA:.+]] = alloca %[[LAMBDA_TY]]
  24
  25 // Copy a pointer to the binding, for reference capture.
  26 // CHECK: %[[LAMBDA_CAP_PTR:.+]] = getelementptr inbounds %[[LAMBDA_TY]], ptr %[[LAMBDA]], i32 0, i32 0
  27 // CHECK: %[[BINDING_PTR:.+]] = getelementptr inbounds %struct.S, ptr %[[BINDING]], i32 0, i32 0
  28 // CHECK: store ptr %[[BINDING_PTR]], ptr %[[LAMBDA_CAP_PTR]]
  29
  30 // Copy the integer from the binding, for copy capture.
  31 // CHECK: %[[LAMBDA_CAP_INT:.+]] = getelementptr inbounds %[[LAMBDA_TY]], ptr %[[LAMBDA]], i32 0, i32 1
  32 // CHECK: %[[PTR_TO_J:.+]] = getelementptr inbounds %struct.S, ptr %[[BINDING]], i32 0, i32 1
  33 // CHECK: %[[J_COPY:.+]] = load i32, ptr %[[PTR_TO_J]]
  34 // CHECK: store i32 %[[J_COPY]], ptr %[[LAMBDA_CAP_INT]]
  35
  36 // Ensure the captures are properly extracted in operator().
  37 // CHECK: define{{.*}} i32 @"_ZZ1fvENK3$_0clEv"
  38 // CHECK: %[[THIS_ADDR:.+]] = alloca ptr
  39 // CHECK: %[[THIS_PTR:.+]] = load ptr, ptr %[[THIS_ADDR]]
  40
  41 // Load 'i', passed by reference.
  42 // CHECK: %[[LAMBDA_GEP_TO_PTR:.+]] = getelementptr inbounds %[[LAMBDA_TY]], ptr %[[THIS_PTR]], i32 0, i32 0
  43 // CHECK: %[[I_PTR:.+]] = load ptr, ptr %[[LAMBDA_GEP_TO_PTR]]
  44 // CHECK: %[[I_VALUE:.+]] = load i32, ptr %[[I_PTR]]
  45
  46 // Load the 'j', passed by value.
  47 // CHECK: %[[LAMBDA_GEP_TO_INT:.+]] = getelementptr inbounds %[[LAMBDA_TY]], ptr %[[THIS_PTR]], i32 0, i32 1
  48 // CHECK: %[[J_VALUE:.+]] = load i32, ptr %[[LAMBDA_GEP_TO_INT]]