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      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() {
      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, i32* [[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]], i32* [[A]]
     14 
     15   a = 42;
     16 // CHECK:  store i32 42, i32* [[A]]
     17 
     18   asm volatile("; %0 This asm uses rsi" : : "r"(a));
     19 // CHECK:  [[TMP:%[a-zA-Z0-9]+]] = load i32, i32* [[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, i32* [[A]]
     24 // CHECK:  ret i32 [[TMP1]]
     25 }
     26 
     27 int earlyclobber() {
     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, i32* [[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]], i32* [[A]]
     37 
     38   a = 42;
     39 // CHECK:  store i32 42, i32* [[A]]
     40 
     41   asm volatile("; %0 This asm uses rsi" : : "r"(a));
     42 // CHECK:  [[TMP:%[a-zA-Z0-9]+]] = load i32, i32* [[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, i32* [[A]]
     47 // CHECK:  ret i32 [[TMP1]]
     48 }
     49