clobber_memory_assembly_test.cc
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#include <benchmark/benchmark.h>
#ifdef __clang__
#pragma clang diagnostic ignored "-Wreturn-type"
#endif
extern "C" {
extern int ExternInt;
extern int ExternInt2;
extern int ExternInt3;
}
// CHECK-LABEL: test_basic:
extern "C" void test_basic() {
int x;
benchmark::DoNotOptimize(&x);
x = 101;
benchmark::ClobberMemory();
// CHECK: leaq [[DEST:[^,]+]], %rax
// CHECK: movl $101, [[DEST]]
// CHECK: ret
}
// CHECK-LABEL: test_redundant_store:
extern "C" void test_redundant_store() {
ExternInt = 3;
benchmark::ClobberMemory();
ExternInt = 51;
// CHECK-DAG: ExternInt
// CHECK-DAG: movl $3
// CHECK: movl $51
}
// CHECK-LABEL: test_redundant_read:
extern "C" void test_redundant_read() {
int x;
benchmark::DoNotOptimize(&x);
x = ExternInt;
benchmark::ClobberMemory();
x = ExternInt2;
// CHECK: leaq [[DEST:[^,]+]], %rax
// CHECK: ExternInt(%rip)
// CHECK: movl %eax, [[DEST]]
// CHECK-NOT: ExternInt2
// CHECK: ret
}
// CHECK-LABEL: test_redundant_read2:
extern "C" void test_redundant_read2() {
int x;
benchmark::DoNotOptimize(&x);
x = ExternInt;
benchmark::ClobberMemory();
x = ExternInt2;
benchmark::ClobberMemory();
// CHECK: leaq [[DEST:[^,]+]], %rax
// CHECK: ExternInt(%rip)
// CHECK: movl %eax, [[DEST]]
// CHECK: ExternInt2(%rip)
// CHECK: movl %eax, [[DEST]]
// CHECK: ret
}