diff --git a/src/hotspot/cpu/x86/c1_LIRAssembler_x86.cpp b/src/hotspot/cpu/x86/c1_LIRAssembler_x86.cpp
index 2faaa6f9ce6..61644e46f39 100644
--- a/src/hotspot/cpu/x86/c1_LIRAssembler_x86.cpp
+++ b/src/hotspot/cpu/x86/c1_LIRAssembler_x86.cpp
@@ -1481,7 +1481,6 @@ void LIR_Assembler::emit_opTypeCheck(LIR_OpTypeCheck* op) {
       __ load_klass(recv, value, tmp_load_klass);
       type_profile_helper(mdo, md, data, recv, Rtmp1);
     } else {
-      __ testptr(value, value);
       __ jcc(Assembler::equal, done);
     }
 
diff --git a/src/hotspot/cpu/x86/c1_MacroAssembler_x86.cpp b/src/hotspot/cpu/x86/c1_MacroAssembler_x86.cpp
index 30470e023c7..99358c023d0 100644
--- a/src/hotspot/cpu/x86/c1_MacroAssembler_x86.cpp
+++ b/src/hotspot/cpu/x86/c1_MacroAssembler_x86.cpp
@@ -272,10 +272,17 @@ void C1_MacroAssembler::step_random(Register state, Register temp) {
   // One of these will be the best for a particular CPU.
 
   if (VM_Version::supports_sse4_2()) {
+#ifndef PRODUCT
+    Label not_zero;
+    orl(r_profile_rng, r_profile_rng);
+    jcc(Assembler::notZero, not_zero);
+    stop("non-zero required before step");
+    bind(not_zero);
+#endif
     /* CRC used as a pseudo-random-number generator */
     // In effect, the CRC instruction is being used here for its
     // linear feedback shift register.
-    movl(temp, 0);
+    xorl(temp, temp);
     crc32(state, temp, /*sizeInBytes*/2);
   } else {
     /* LCG by Marsaglia. From Karl Entacher,
@@ -288,6 +295,13 @@ void C1_MacroAssembler::step_random(Register state, Register temp) {
 
 void C1_MacroAssembler::save_profile_rng() {
   if (ProfileCaptureRatio > 1) {
+#ifndef PRODUCT
+    Label not_zero;
+    orl(r_profile_rng, r_profile_rng);
+    jcc(Assembler::notZero, not_zero);
+    stop("non-zero required before save");
+    bind(not_zero);
+#endif
     movl(Address(r15_thread, JavaThread::profile_rng_offset()), r_profile_rng);
   }
 }
@@ -295,6 +309,13 @@ void C1_MacroAssembler::save_profile_rng() {
 void C1_MacroAssembler::restore_profile_rng() {
   if (ProfileCaptureRatio > 1) {
     movl(r_profile_rng, Address(r15_thread, JavaThread::profile_rng_offset()));
+#ifndef PRODUCT
+    Label not_zero;
+    orl(r_profile_rng, r_profile_rng);
+    jcc(Assembler::notZero, not_zero);
+    stop("non-zero required after restore");
+    bind(not_zero);
+#endif
   }
 }