diff --git a/compiler-rt/test/msan/CMakeLists.txt b/compiler-rt/test/msan/CMakeLists.txt
--- a/compiler-rt/test/msan/CMakeLists.txt
+++ b/compiler-rt/test/msan/CMakeLists.txt
@@ -8,7 +8,7 @@
   darwin_filter_host_archs(MSAN_SUPPORTED_ARCH MSAN_TEST_ARCH)
 endif()
 
-macro(add_msan_testsuite arch lld thinlto)
+macro(add_msan_testsuite arch lld thinlto eager)
   set(MSAN_TEST_TARGET_ARCH ${arch})
   get_test_cc_for_arch(${arch} MSAN_TEST_TARGET_CC MSAN_TEST_TARGET_CFLAGS)
 
@@ -24,8 +24,12 @@
       list(APPEND MSAN_TEST_DEPS lld)
     endif()
   endif()
+  if (${eager})
+    set(CONFIG_NAME "eager-${CONFIG_NAME}")
+  endif()
   set(MSAN_TEST_USE_THINLTO ${thinlto})
   set(MSAN_TEST_USE_LLD ${lld})
+  set(MSAN_TEST_EAGER_CHECK ${eager})
 
   configure_lit_site_cfg(
     ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.py.in
@@ -34,10 +38,11 @@
 endmacro()
 
 foreach(arch ${MSAN_TEST_ARCH})
-  add_msan_testsuite(${arch} False False)
+  add_msan_testsuite(${arch} False False False)
+  add_msan_testsuite(${arch} False False True)
 
   if(COMPILER_RT_HAS_LLD AND arch STREQUAL "x86_64" AND NOT (APPLE OR WIN32))
-    add_msan_testsuite(${arch} True False)
+    add_msan_testsuite(${arch} True False False)
   endif()
 endforeach()
 
diff --git a/compiler-rt/test/msan/chained_origin.cpp b/compiler-rt/test/msan/chained_origin.cpp
--- a/compiler-rt/test/msan/chained_origin.cpp
+++ b/compiler-rt/test/msan/chained_origin.cpp
@@ -20,12 +20,12 @@
 volatile int x, y;
 
 __attribute__((noinline))
-void fn_g(int a) {
+void fn_g(volatile int &a) {
   x = a;
 }
 
 __attribute__((noinline))
-void fn_f(int a) {
+void fn_f(volatile int &a) {
   fn_g(a);
 }
 
diff --git a/compiler-rt/test/msan/chained_origin_empty_stack.cpp b/compiler-rt/test/msan/chained_origin_empty_stack.cpp
--- a/compiler-rt/test/msan/chained_origin_empty_stack.cpp
+++ b/compiler-rt/test/msan/chained_origin_empty_stack.cpp
@@ -18,12 +18,12 @@
 volatile int x;
 
 __attribute__((noinline))
-void fn_g(int a) {
+void fn_g(volatile int &a) {
   x = a;
 }
 
 __attribute__((noinline))
-void fn_f(int a) {
+void fn_f(volatile int &a) {
   fn_g(a);
 }
 
diff --git a/compiler-rt/test/msan/chained_origin_memcpy.cpp b/compiler-rt/test/msan/chained_origin_memcpy.cpp
--- a/compiler-rt/test/msan/chained_origin_memcpy.cpp
+++ b/compiler-rt/test/msan/chained_origin_memcpy.cpp
@@ -23,12 +23,12 @@
 volatile int idx = 30;
 
 __attribute__((noinline))
-void fn_g(int a, int b) {
+void fn_g(volatile int &a, volatile int &b) {
   xx[idx] = a; xx[idx + 10] = b;
 }
 
 __attribute__((noinline))
-void fn_f(int a, int b) {
+void fn_f(volatile int &a, volatile int &b) {
   fn_g(a, b);
 }
 
diff --git a/compiler-rt/test/msan/cxa_atexit.cpp b/compiler-rt/test/msan/cxa_atexit.cpp
--- a/compiler-rt/test/msan/cxa_atexit.cpp
+++ b/compiler-rt/test/msan/cxa_atexit.cpp
@@ -1,4 +1,5 @@
 // RUN: %clangxx_msan -O0 %s -o %t && %run %t %p
+// REQUIRES: !msan_eager_checks
 
 // PR17377: C++ module destructors get stale argument shadow.
 
diff --git a/compiler-rt/test/msan/insertvalue_origin.cpp b/compiler-rt/test/msan/insertvalue_origin.cpp
--- a/compiler-rt/test/msan/insertvalue_origin.cpp
+++ b/compiler-rt/test/msan/insertvalue_origin.cpp
@@ -13,7 +13,7 @@
  int y;
 };
 
-mypair my_make_pair(int64_t x, int y)  {
+mypair my_make_pair(const int64_t &x, const int &y)  {
  mypair p;
  p.x = x;
  p.y = y;
diff --git a/compiler-rt/test/msan/lit.site.cfg.py.in b/compiler-rt/test/msan/lit.site.cfg.py.in
--- a/compiler-rt/test/msan/lit.site.cfg.py.in
+++ b/compiler-rt/test/msan/lit.site.cfg.py.in
@@ -7,6 +7,10 @@
 config.use_lld = @MSAN_TEST_USE_LLD@
 config.use_thinlto = @MSAN_TEST_USE_THINLTO@
 
+if @MSAN_TEST_EAGER_CHECK@:
+  config.target_cflags += " -mllvm -msan-eager-checks -DTEST_MSAN_EAGER_CHECKS"
+  config.available_features.add('msan_eager_checks')
+
 # Load common config for all compiler-rt lit tests.
 lit_config.load_config(config, "@COMPILER_RT_BINARY_DIR@/test/lit.common.configured")
 
diff --git a/compiler-rt/test/msan/no_sanitize_memory_prop.cpp b/compiler-rt/test/msan/no_sanitize_memory_prop.cpp
--- a/compiler-rt/test/msan/no_sanitize_memory_prop.cpp
+++ b/compiler-rt/test/msan/no_sanitize_memory_prop.cpp
@@ -11,7 +11,7 @@
 __attribute__((noinline))
 __attribute__((weak))
 __attribute__((no_sanitize_memory))
-int f(int x) {
+int f(int &x) {
   return x;
 }
 
diff --git a/compiler-rt/test/msan/param_tls_limit.cpp b/compiler-rt/test/msan/param_tls_limit.cpp
--- a/compiler-rt/test/msan/param_tls_limit.cpp
+++ b/compiler-rt/test/msan/param_tls_limit.cpp
@@ -4,6 +4,7 @@
 // RUN: %clangxx_msan -O0 %s -o %t && %run %t
 // RUN: %clangxx_msan -fsanitize-memory-track-origins -O0 %s -o %t && %run %t
 // RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -O0 %s -o %t && %run %t
+// REQUIRES: !msan_eager_checks
 //
 // AArch64 fails with:
 // void f801(S<801>): Assertion `__msan_test_shadow(&s, sizeof(s)) == -1' failed
diff --git a/compiler-rt/test/msan/qsort.cpp b/compiler-rt/test/msan/qsort.cpp
--- a/compiler-rt/test/msan/qsort.cpp
+++ b/compiler-rt/test/msan/qsort.cpp
@@ -19,8 +19,10 @@
 
 void poison_stack_and_param() {
   char x[10000];
+#ifndef TEST_MSAN_EAGER_CHECKS
   int y;
   dummy(y, y, y, y, y);
+#endif
 }
 
 __attribute__((always_inline)) int cmp(long a, long b) {
diff --git a/compiler-rt/test/msan/signal_stress_test.cpp b/compiler-rt/test/msan/signal_stress_test.cpp
--- a/compiler-rt/test/msan/signal_stress_test.cpp
+++ b/compiler-rt/test/msan/signal_stress_test.cpp
@@ -4,6 +4,7 @@
 
 // Reported deadly signal due to stack-overflow
 // XFAIL: netbsd
+// XFAIL: msan_eager_checks
 
 #include <signal.h>
 #include <stdarg.h>
diff --git a/compiler-rt/test/msan/stack-origin2.cpp b/compiler-rt/test/msan/stack-origin2.cpp
--- a/compiler-rt/test/msan/stack-origin2.cpp
+++ b/compiler-rt/test/msan/stack-origin2.cpp
@@ -18,6 +18,8 @@
 // RUN: %clangxx_msan -fsanitize-memory-track-origins -O3 %s -o %t && not %run %t >%t.out 2>&1
 // RUN: FileCheck %s < %t.out && FileCheck %s --check-prefix=CHECK-ORIGINS < %t.out
 
+// REQUIRES: !msan_eager_checks
+
 #include <stdlib.h>
 
 extern "C"
diff --git a/compiler-rt/test/msan/unpoison_param.cpp b/compiler-rt/test/msan/unpoison_param.cpp
--- a/compiler-rt/test/msan/unpoison_param.cpp
+++ b/compiler-rt/test/msan/unpoison_param.cpp
@@ -5,6 +5,7 @@
 // RUN: %clangxx_msan -fno-sanitize=memory -c %s -o %t-main.o
 // RUN: %clangxx_msan %t-main.o %s -o %t
 // RUN: %run %t
+// REQUIRES: !msan_eager_checks
 
 #include <assert.h>
 #include <sanitizer/msan_interface.h>
diff --git a/compiler-rt/test/msan/vararg.cpp b/compiler-rt/test/msan/vararg.cpp
--- a/compiler-rt/test/msan/vararg.cpp
+++ b/compiler-rt/test/msan/vararg.cpp
@@ -1,16 +1,24 @@
-// RUN: %clangxx_msan -fsanitize-memory-track-origins=0 -O3 %s -o %t && \
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=0 -DEXPECT_PASS -O3 %s -o %t && \
+// RUN:     not %run %t va_arg_tls >%t.out 2>&1
+// RUN: not [ -s %t.out ]
+
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=0 -DEXPECT_PASS -O3 %s -o %t && \
+// RUN:     not %run %t overflow >%t.out 2>&1
+// RUN: not [ -s %t.out ]
+ 
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=0 -DEXPECT_FAIL -O3 %s -o %t && \
 // RUN:     not %run %t va_arg_tls >%t.out 2>&1
 // RUN: FileCheck %s --check-prefix=CHECK < %t.out
 
-// RUN: %clangxx_msan -fsanitize-memory-track-origins=0 -O3 %s -o %t && \
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=0 -DEXPECT_FAIL -O3 %s -o %t && \
 // RUN:     not %run %t overflow >%t.out 2>&1
 // RUN: FileCheck %s --check-prefix=CHECK < %t.out
 
-// RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -O3 %s -o %t && \
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -DEXPECT_FAIL -O3 %s -o %t && \
 // RUN:     not %run %t va_arg_tls >%t.out 2>&1
 // RUN: FileCheck %s --check-prefixes=CHECK,CHECK-ORIGIN < %t.out
 
-// RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -O3 %s -o %t && \
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -DEXPECT_FAIL -O3 %s -o %t && \
 // RUN:     not %run %t overflow >%t.out 2>&1
 // RUN: FileCheck %s --check-prefixes=CHECK,CHECK-ORIGIN < %t.out
 
@@ -24,6 +32,22 @@
 #include <stdarg.h>
 #include <string.h>
 
+#include <sanitizer/msan_interface.h>
+
+__attribute__((noinline))
+void dummy(long a, long b, long c, long d, long e) {
+  __asm__ __volatile__ (""::"r"(a), "r"(b), "r"(c), "r"(d), "r"(e));
+}
+
+__attribute__((noinline))
+void poison_stack_and_param() {
+  char x[10000];
+#ifndef TEST_MSAN_EAGER_CHECKS
+  int y;
+  dummy(y, y, y, y, y);
+#endif
+}
+
 __attribute__((noinline))
 int sum(int n, ...) {
   va_list args;
@@ -39,15 +63,28 @@
 }
 
 int main(int argc, char *argv[]) {
+#if defined(EXPECT_FAIL)
   volatile int uninit;
+  #define PRE_RUN for (int i = 0; i < 6; i++) __msan_unpoison_param(i)
+  // CHECK: WARNING: MemorySanitizer: use-of-uninitialized-value
+  // CHECK-ORIGIN: Uninitialized value was created by an allocation of 'uninit' in the stack frame of function 'main'
+#elif defined(EXPECT_PASS)
+  volatile int uninit = 0;
+  #define PRE_RUN poison_stack_and_param()
+#else
+  #error Bad configuration
+#endif
+
   volatile int a = 1, b = 2;
   if (argc == 2) {
     // Shadow/origin will be passed via va_arg_tls/va_arg_origin_tls.
     if (strcmp(argv[1], "va_arg_tls") == 0) {
+      PRE_RUN;
       return sum(3, uninit, a, b);
     }
     // Shadow/origin of |uninit| will be passed via overflow area.
     if (strcmp(argv[1], "overflow") == 0) {
+      PRE_RUN;
       return sum(7,
         a, a, a, a, a, a, uninit
       );
@@ -55,6 +92,3 @@
   }
   return 0;
 }
-
-// CHECK: WARNING: MemorySanitizer: use-of-uninitialized-value
-// CHECK-ORIGIN: Uninitialized value was created by an allocation of 'uninit' in the stack frame of function 'main'
diff --git a/compiler-rt/test/msan/vector_cvt.cpp b/compiler-rt/test/msan/vector_cvt.cpp
--- a/compiler-rt/test/msan/vector_cvt.cpp
+++ b/compiler-rt/test/msan/vector_cvt.cpp
@@ -4,7 +4,7 @@
 
 #include <emmintrin.h>
 
-int to_int(double v) {
+int to_int(double &v) {
   __m128d t = _mm_set_sd(v);
   int x = _mm_cvtsd_si32(t);
   return x;