8264945: Optimize the code-gen for Math.pow(x, 0.5)
Reviewed-by: neliasso, kvn
diff --git a/src/hotspot/share/opto/library_call.cpp b/src/hotspot/share/opto/library_call.cpp
index 2fdc7f7..7cb7955 100644
--- a/src/hotspot/share/opto/library_call.cpp
+++ b/src/hotspot/share/opto/library_call.cpp
@@ -1633,6 +1633,65 @@
return true;
}
+//------------------------------inline_math_pow-----------------------------
+bool LibraryCallKit::inline_math_pow() {
+ Node* exp = round_double_node(argument(2));
+ const TypeD* d = _gvn.type(exp)->isa_double_constant();
+ if (d != NULL) {
+ if (d->getd() == 2.0) {
+ // Special case: pow(x, 2.0) => x * x
+ Node* base = round_double_node(argument(0));
+ set_result(_gvn.transform(new MulDNode(base, base)));
+ return true;
+ }
+#if defined(X86) && defined(_LP64)
+ else if (d->getd() == 0.5 && Matcher::match_rule_supported(Op_SqrtD)) {
+ // Special case: pow(x, 0.5) => sqrt(x)
+ Node* base = round_double_node(argument(0));
+ Node* zero = _gvn.zerocon(T_DOUBLE);
+
+ RegionNode* region = new RegionNode(3);
+ Node* phi = new PhiNode(region, Type::DOUBLE);
+
+ Node* cmp = _gvn.transform(new CmpDNode(base, zero));
+ Node* test = _gvn.transform(new BoolNode(cmp, BoolTest::lt));
+
+ Node* if_pow = generate_slow_guard(test, NULL);
+ Node* value_sqrt = _gvn.transform(new SqrtDNode(C, control(), base));
+ phi->init_req(1, value_sqrt);
+ region->init_req(1, control());
+
+ if (if_pow != NULL) {
+ set_control(if_pow);
+ address target = StubRoutines::dpow() != NULL ? StubRoutines::dpow() :
+ CAST_FROM_FN_PTR(address, SharedRuntime::dpow);
+ const TypePtr* no_memory_effects = NULL;
+ Node* trig = make_runtime_call(RC_LEAF, OptoRuntime::Math_DD_D_Type(), target, "POW",
+ no_memory_effects, base, top(), exp, top());
+ Node* value_pow = _gvn.transform(new ProjNode(trig, TypeFunc::Parms+0));
+#ifdef ASSERT
+ Node* value_top = _gvn.transform(new ProjNode(trig, TypeFunc::Parms+1));
+ assert(value_top == top(), "second value must be top");
+#endif
+ phi->init_req(2, value_pow);
+ region->init_req(2, _gvn.transform(new ProjNode(trig, TypeFunc::Control)));
+ }
+
+ C->set_has_split_ifs(true); // Has chance for split-if optimization
+ set_control(_gvn.transform(region));
+ record_for_igvn(region);
+ set_result(_gvn.transform(phi));
+
+ return true;
+ }
+#endif // defined(X86) && defined(_LP64)
+ }
+
+ return StubRoutines::dpow() != NULL ?
+ runtime_math(OptoRuntime::Math_DD_D_Type(), StubRoutines::dpow(), "dpow") :
+ runtime_math(OptoRuntime::Math_DD_D_Type(), CAST_FROM_FN_PTR(address, SharedRuntime::dpow), "POW");
+}
+
//------------------------------inline_math_native-----------------------------
bool LibraryCallKit::inline_math_native(vmIntrinsics::ID id) {
#define FN_PTR(f) CAST_FROM_FN_PTR(address, f)
@@ -1673,21 +1732,9 @@
return StubRoutines::dexp() != NULL ?
runtime_math(OptoRuntime::Math_D_D_Type(), StubRoutines::dexp(), "dexp") :
runtime_math(OptoRuntime::Math_D_D_Type(), FN_PTR(SharedRuntime::dexp), "EXP");
- case vmIntrinsics::_dpow: {
- Node* exp = round_double_node(argument(2));
- const TypeD* d = _gvn.type(exp)->isa_double_constant();
- if (d != NULL && d->getd() == 2.0) {
- // Special case: pow(x, 2.0) => x * x
- Node* base = round_double_node(argument(0));
- set_result(_gvn.transform(new MulDNode(base, base)));
- return true;
- }
- return StubRoutines::dpow() != NULL ?
- runtime_math(OptoRuntime::Math_DD_D_Type(), StubRoutines::dpow(), "dpow") :
- runtime_math(OptoRuntime::Math_DD_D_Type(), FN_PTR(SharedRuntime::dpow), "POW");
- }
#undef FN_PTR
+ case vmIntrinsics::_dpow: return inline_math_pow();
case vmIntrinsics::_dcopySign: return inline_double_math(id);
case vmIntrinsics::_fcopySign: return inline_math(id);
case vmIntrinsics::_dsignum: return inline_double_math(id);
diff --git a/src/hotspot/share/opto/library_call.hpp b/src/hotspot/share/opto/library_call.hpp
index 5ddb48c..13c5670 100644
--- a/src/hotspot/share/opto/library_call.hpp
+++ b/src/hotspot/share/opto/library_call.hpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -201,6 +201,7 @@
bool inline_math_native(vmIntrinsics::ID id);
bool inline_math(vmIntrinsics::ID id);
bool inline_double_math(vmIntrinsics::ID id);
+ bool inline_math_pow();
template <typename OverflowOp>
bool inline_math_overflow(Node* arg1, Node* arg2);
void inline_math_mathExact(Node* math, Node* test);
