clang/test/CodeGen/asm-reg-var-local.c

   1 // RUN: %clang_cc1 %s -triple x86_64-apple-darwin -emit-llvm -o - | FileCheck %s
   2 // Exercise various use cases for local asm "register variables".
   3
   4 int foo(void) {
   5 // CHECK-LABEL: define{{.*}} i32 @foo()
   6 // CHECK: [[A:%[a-zA-Z0-9]+]] = alloca i32
   7
   8   register int a asm("rsi")=5;
   9 // CHECK: store i32 5, ptr [[A]]
  10
  11   asm volatile("; %0 This asm defines rsi" : "=r"(a));
  12 // CHECK: [[Z:%[a-zA-Z0-9]+]] = call i32 asm sideeffect "; $0 This asm defines rsi", "={rsi},~{dirflag},~{fpsr},~{flags}"()
  13 // CHECK: store i32 [[Z]], ptr [[A]]
  14
  15   a = 42;
  16 // CHECK:  store i32 42, ptr [[A]]
  17
  18   asm volatile("; %0 This asm uses rsi" : : "r"(a));
  19 // CHECK:  [[TMP:%[a-zA-Z0-9]+]] = load i32, ptr [[A]]
  20 // CHECK:  call void asm sideeffect "; $0 This asm uses rsi", "{rsi},~{dirflag},~{fpsr},~{flags}"(i32 [[TMP]])
  21
  22   return a;
  23 // CHECK:  [[TMP1:%[a-zA-Z0-9]+]] = load i32, ptr [[A]]
  24 // CHECK:  ret i32 [[TMP1]]
  25 }
  26
  27 int earlyclobber(void) {
  28 // CHECK-LABEL: define{{.*}} i32 @earlyclobber()
  29 // CHECK: [[A:%[a-zA-Z0-9]+]] = alloca i32
  30
  31   register int a asm("rsi")=5;
  32 // CHECK: store i32 5, ptr [[A]]
  33
  34   asm volatile("; %0 This asm defines rsi" : "=&r"(a));
  35 // CHECK: [[Z:%[a-zA-Z0-9]+]] = call i32 asm sideeffect "; $0 This asm defines rsi", "=&{rsi},~{dirflag},~{fpsr},~{flags}"()
  36 // CHECK: store i32 [[Z]], ptr [[A]]
  37
  38   a = 42;
  39 // CHECK:  store i32 42, ptr [[A]]
  40
  41   asm volatile("; %0 This asm uses rsi" : : "r"(a));
  42 // CHECK:  [[TMP:%[a-zA-Z0-9]+]] = load i32, ptr [[A]]
  43 // CHECK:  call void asm sideeffect "; $0 This asm uses rsi", "{rsi},~{dirflag},~{fpsr},~{flags}"(i32 [[TMP]])
  44
  45   return a;
  46 // CHECK:  [[TMP1:%[a-zA-Z0-9]+]] = load i32, ptr [[A]]
  47 // CHECK:  ret i32 [[TMP1]]
  48 }