xref: /llvm-project/clang/test/CodeGen/assign.c (revision 39db5e1ed87363a9ffea81e53520b542201b3262)
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: }
f0(void)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: }
f1(void)28 void f1(void) {
29   volatile int x, y;
30   x = 1;
31   y = (x = 1);
32 }
33