8257483: C2: Split immediate vector rotate from RotateLeftV and RotateRightV nodes

Reviewed-by: vlivanov

src/hotspot/cpu/aarch64/aarch64.ad

@@ -2437,6 +2437,10 @@ bool Matcher::supports_vector_variable_shifts(void) {
   return true;
 }
 
+bool Matcher::supports_vector_variable_rotates(void) {
+  return false; // not supported
+}
+
 const int Matcher::float_pressure(int default_pressure_threshold) {
   return default_pressure_threshold;
 }

src/hotspot/cpu/arm/arm.ad

@@ -997,6 +997,10 @@ bool Matcher::supports_vector_variable_shifts(void) {
   return VM_Version::has_simd();
 }
 
+bool Matcher::supports_vector_variable_rotates(void) {
+  return false; // not supported
+}
+
 const int Matcher::float_pressure(int default_pressure_threshold) {
   return default_pressure_threshold;
 }

src/hotspot/cpu/ppc/ppc.ad

@@ -2155,6 +2155,10 @@ bool Matcher::supports_vector_variable_shifts(void) {
   return false; // not supported
 }
 
+bool Matcher::supports_vector_variable_rotates(void) {
+  return false; // not supported
+}
+
 const int Matcher::float_pressure(int default_pressure_threshold) {
   return default_pressure_threshold;
 }

src/hotspot/cpu/s390/s390.ad

@@ -1550,6 +1550,10 @@ bool Matcher::supports_vector_variable_shifts(void) {
   return false; // not supported
 }
 
+bool Matcher::supports_vector_variable_rotates(void) {
+  return false; // not supported
+}
+
 const int Matcher::float_pressure(int default_pressure_threshold) {
   return default_pressure_threshold;
 }

src/hotspot/cpu/x86/x86.ad

@@ -1814,6 +1814,10 @@ bool Matcher::supports_vector_variable_shifts(void) {
   return (UseAVX >= 2);
 }
 
+bool Matcher::supports_vector_variable_rotates(void) {
+  return true;
+}
+
 const bool Matcher::has_predicated_vectors(void) {
   bool ret_value = false;
   if (UseAVX > 2) {

src/hotspot/share/opto/matcher.hpp

@@ -348,6 +348,9 @@ public:
   // Does the CPU supports vector variable shift instructions?
   static bool supports_vector_variable_shifts(void);
 
+  // Does the CPU supports vector vairable rotate instructions?
+  static bool supports_vector_variable_rotates(void);
+
   // CPU supports misaligned vectors store/load.
   static const bool misaligned_vectors_ok();
 

src/hotspot/share/opto/vectornode.cpp

@@ -1172,7 +1172,8 @@ Node* VectorNode::degenerate_vector_rotate(Node* src, Node* cnt, bool is_rotate_
 Node* RotateLeftVNode::Ideal(PhaseGVN* phase, bool can_reshape) {
   int vlen = length();
   BasicType bt = vect_type()->element_basic_type();
-  if (!Matcher::match_rule_supported_vector(Op_RotateLeftV, vlen, bt)) {
+  if ((!in(2)->is_Con() && !Matcher::supports_vector_variable_rotates()) ||
+       !Matcher::match_rule_supported_vector(Op_RotateLeftV, vlen, bt)) {
     return VectorNode::degenerate_vector_rotate(in(1), in(2), true, vlen, bt, phase);
   }
   return NULL;
@@ -1181,7 +1182,8 @@ Node* RotateLeftVNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 Node* RotateRightVNode::Ideal(PhaseGVN* phase, bool can_reshape) {
   int vlen = length();
   BasicType bt = vect_type()->element_basic_type();
-  if (!Matcher::match_rule_supported_vector(Op_RotateRightV, vlen, bt)) {
+  if ((!in(2)->is_Con() && !Matcher::supports_vector_variable_rotates()) ||
+       !Matcher::match_rule_supported_vector(Op_RotateRightV, vlen, bt)) {
     return VectorNode::degenerate_vector_rotate(in(1), in(2), false, vlen, bt, phase);
   }
   return NULL;