src/cpu/x86/vm/x86_32.ad

@@ -1418,13 +1418,10 @@
 }
 
 // The ecx parameter to rep stos for the ClearArray node is in dwords.
 const bool Matcher::init_array_count_is_in_bytes = false;
 
-// Threshold size for cleararray.
-const int Matcher::init_array_short_size = 8 * BytesPerLong;
-
 // Needs 2 CMOV's for longs.
 const int Matcher::long_cmove_cost() { return 1; }
 
 // No CMOVF/CMOVD with SSE/SSE2
 const int Matcher::float_cmove_cost() { return (UseSSE>=1) ? ConditionalMoveLimit : 0; }

@@ -11367,31 +11364,57 @@
 
 
 // =======================================================================
 // fast clearing of an array
 instruct rep_stos(eCXRegI cnt, eDIRegP base, eAXRegI zero, Universe dummy, eFlagsReg cr) %{
-  predicate(!UseFastStosb);
+  predicate(!UseFastStosb && !((ClearArrayNode*)n)->is_large());
+  match(Set dummy (ClearArray cnt base));
+  effect(USE_KILL cnt, USE_KILL base, KILL zero, KILL cr);
+  format %{ "XOR    EAX,EAX\t# ClearArray:\n\t"
+            "SHL    ECX,1\t# Convert doublewords to words\n\t"
+            "REP STOS\t# store EAX into [EDI++] while ECX--" %}
+  ins_encode %{
+    __ clear_mem($base$$Register, $cnt$$Register, $zero$$Register, false);
+  %}
+  ins_pipe( pipe_slow );
+%}
+
+instruct rep_stos_large(eCXRegI cnt, eDIRegP base, eAXRegI zero, Universe dummy, eFlagsReg cr) %{
+  predicate(!UseFastStosb && ((ClearArrayNode*)n)->is_large());
   match(Set dummy (ClearArray cnt base));
   effect(USE_KILL cnt, USE_KILL base, KILL zero, KILL cr);
   format %{ "XOR    EAX,EAX\t# ClearArray:\n\t"
             "SHL    ECX,1\t# Convert doublewords to words\n\t"
             "REP STOS\t# store EAX into [EDI++] while ECX--" %}
   ins_encode %{
-    __ clear_mem($base$$Register, $cnt$$Register, $zero$$Register);
+    __ clear_mem($base$$Register, $cnt$$Register, $zero$$Register, true);
   %}
   ins_pipe( pipe_slow );
 %}
 
 instruct rep_fast_stosb(eCXRegI cnt, eDIRegP base, eAXRegI zero, Universe dummy, eFlagsReg cr) %{
-  predicate(UseFastStosb);
+  predicate(UseFastStosb && !((ClearArrayNode*)n)->is_large());
+  match(Set dummy (ClearArray cnt base));
+  effect(USE_KILL cnt, USE_KILL base, KILL zero, KILL cr);
+  format %{ "XOR    EAX,EAX\t# ClearArray:\n\t"
+            "SHL    ECX,3\t# Convert doublewords to bytes\n\t"
+            "REP STOSB\t# store EAX into [EDI++] while ECX--" %}
+  ins_encode %{
+    __ clear_mem($base$$Register, $cnt$$Register, $zero$$Register, false);
+  %}
+  ins_pipe( pipe_slow );
+%}
+
+instruct rep_fast_stosb_large(eCXRegI cnt, eDIRegP base, eAXRegI zero, Universe dummy, eFlagsReg cr) %{
+  predicate(UseFastStosb && ((ClearArrayNode*)n)->is_large());
   match(Set dummy (ClearArray cnt base));
   effect(USE_KILL cnt, USE_KILL base, KILL zero, KILL cr);
   format %{ "XOR    EAX,EAX\t# ClearArray:\n\t"
             "SHL    ECX,3\t# Convert doublewords to bytes\n\t"
             "REP STOSB\t# store EAX into [EDI++] while ECX--" %}
   ins_encode %{
-    __ clear_mem($base$$Register, $cnt$$Register, $zero$$Register);
+    __ clear_mem($base$$Register, $cnt$$Register, $zero$$Register, true);
   %}
   ins_pipe( pipe_slow );
 %}
 
 instruct string_compareL(eDIRegP str1, eCXRegI cnt1, eSIRegP str2, eDXRegI cnt2,