utils/benchmark/test/clobber_memory_assembly_test.cc

   1 #include <benchmark/benchmark.h>
   2
   3 #ifdef __clang__
   4 #pragma clang diagnostic ignored "-Wreturn-type"
   5 #endif
   6
   7 extern "C" {
   8
   9 extern int ExternInt;
  10 extern int ExternInt2;
  11 extern int ExternInt3;
  12
  13 }
  14
  15 // CHECK-LABEL: test_basic:
  16 extern "C" void test_basic() {
  17   int x;
  18   benchmark::DoNotOptimize(&x);
  19   x = 101;
  20   benchmark::ClobberMemory();
  21   // CHECK: leaq [[DEST:[^,]+]], %rax
  22   // CHECK: movl $101, [[DEST]]
  23   // CHECK: ret
  24 }
  25
  26 // CHECK-LABEL: test_redundant_store:
  27 extern "C" void test_redundant_store() {
  28   ExternInt = 3;
  29   benchmark::ClobberMemory();
  30   ExternInt = 51;
  31   // CHECK-DAG: ExternInt
  32   // CHECK-DAG: movl $3
  33   // CHECK: movl $51
  34 }
  35
  36 // CHECK-LABEL: test_redundant_read:
  37 extern "C" void test_redundant_read() {
  38   int x;
  39   benchmark::DoNotOptimize(&x);
  40   x = ExternInt;
  41   benchmark::ClobberMemory();
  42   x = ExternInt2;
  43   // CHECK: leaq [[DEST:[^,]+]], %rax
  44   // CHECK: ExternInt(%rip)
  45   // CHECK: movl %eax, [[DEST]]
  46   // CHECK-NOT: ExternInt2
  47   // CHECK: ret
  48 }
  49
  50 // CHECK-LABEL: test_redundant_read2:
  51 extern "C" void test_redundant_read2() {
  52   int x;
  53   benchmark::DoNotOptimize(&x);
  54   x = ExternInt;
  55   benchmark::ClobberMemory();
  56   x = ExternInt2;
  57   benchmark::ClobberMemory();
  58   // CHECK: leaq [[DEST:[^,]+]], %rax
  59   // CHECK: ExternInt(%rip)
  60   // CHECK: movl %eax, [[DEST]]
  61   // CHECK: ExternInt2(%rip)
  62   // CHECK: movl %eax, [[DEST]]
  63   // CHECK: ret
  64 }