clang/test/CodeGen/assign.c

   1 // RUN: %clang_cc1 -triple x86_64 -emit-llvm -o - %s | FileCheck %s
   2
   3 // Check that we don't generate unnecessary reloads.
   4 //
   5 // CHECK-LABEL: define{{.*}} void @f0()
   6 // CHECK:      [[x_0:%.*]] = alloca i32, align 4
   7 // CHECK-NEXT: [[y_0:%.*]] = alloca i32, align 4
   8 // CHECK-NEXT: store i32 1, ptr [[x_0]]
   9 // CHECK-NEXT: store i32 1, ptr [[x_0]]
  10 // CHECK-NEXT: store i32 1, ptr [[y_0]]
  11 // CHECK: }
  12 void f0(void) {
  13   int x, y;
  14   x = 1;
  15   y = (x = 1);
  16 }
  17
  18 // This used to test that we generate reloads for volatile access,
  19 // but that does not appear to be correct behavior for C.
  20 //
  21 // CHECK-LABEL: define{{.*}} void @f1()
  22 // CHECK:      [[x_1:%.*]] = alloca i32, align 4
  23 // CHECK-NEXT: [[y_1:%.*]] = alloca i32, align 4
  24 // CHECK-NEXT: store volatile i32 1, ptr [[x_1]]
  25 // CHECK-NEXT: store volatile i32 1, ptr [[x_1]]
  26 // CHECK-NEXT: store volatile i32 1, ptr [[y_1]]
  27 // CHECK: }
  28 void f1(void) {
  29   volatile int x, y;
  30   x = 1;
  31   y = (x = 1);
  32 }