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java-25-openjdk/jdk8347901-c2_unused_leaf_removal.patch
Andrew Hughes 4fa0394a1a Add 25u backports of JDK-8347901 & JDK-8378713 C2 performance fixes 
Resolves: RHEL-210993
2026-07-15 14:45:51 +01:00

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From 09853461a6896ab1f15469c753c21ca212e7e650 Mon Sep 17 00:00:00 2001
From: duke <duke@openjdk.org>
Date: Tue, 7 Apr 2026 15:14:53 +0000
Subject: [PATCH 1/2] Backport ed70910b0f3e1b19d915ec13ac3434407d01bc5d
---
src/hotspot/share/opto/callnode.cpp | 53 +++++++-
src/hotspot/share/opto/callnode.hpp | 29 ++++-
src/hotspot/share/opto/classes.hpp | 2 +
src/hotspot/share/opto/compile.cpp | 19 +++
src/hotspot/share/opto/divnode.cpp | 158 ++++++++++--------------
src/hotspot/share/opto/divnode.hpp | 35 +++---
src/hotspot/share/opto/graphKit.cpp | 29 +++--
src/hotspot/share/opto/graphKit.hpp | 1 +
src/hotspot/share/opto/library_call.cpp | 2 +-
src/hotspot/share/opto/macro.cpp | 15 +--
src/hotspot/share/opto/multnode.cpp | 13 ++
src/hotspot/share/opto/multnode.hpp | 46 +++++++
src/hotspot/share/opto/node.cpp | 12 +-
src/hotspot/share/opto/node.hpp | 5 +-
src/hotspot/share/opto/parse2.cpp | 8 +-
15 files changed, 282 insertions(+), 145 deletions(-)
diff --git a/src/hotspot/share/opto/callnode.cpp b/src/hotspot/share/opto/callnode.cpp
index 6f13ce0f809..fc4b0c35dff 100644
--- a/src/hotspot/share/opto/callnode.cpp
+++ b/src/hotspot/share/opto/callnode.cpp
@@ -935,7 +935,7 @@ Node *CallNode::result_cast() {
}
-void CallNode::extract_projections(CallProjections* projs, bool separate_io_proj, bool do_asserts) {
+void CallNode::extract_projections(CallProjections* projs, bool separate_io_proj, bool do_asserts) const {
projs->fallthrough_proj = nullptr;
projs->fallthrough_catchproj = nullptr;
projs->fallthrough_ioproj = nullptr;
@@ -1319,6 +1319,57 @@ void CallLeafVectorNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_
//=============================================================================
+bool CallLeafPureNode::is_unused() const {
+ return proj_out_or_null(TypeFunc::Parms) == nullptr;
+}
+
+bool CallLeafPureNode::is_dead() const {
+ return proj_out_or_null(TypeFunc::Control) == nullptr;
+}
+
+/* We make a tuple of the global input state + TOP for the output values.
+ * We use this to delete a pure function that is not used: by replacing the call with
+ * such a tuple, we let output Proj's idealization pick the corresponding input of the
+ * pure call, so jumping over it, and effectively, removing the call from the graph.
+ * This avoids doing the graph surgery manually, but leaves that to IGVN
+ * that is specialized for doing that right. We need also tuple components for output
+ * values of the function to respect the return arity, and in case there is a projection
+ * that would pick an output (which shouldn't happen at the moment).
+ */
+TupleNode* CallLeafPureNode::make_tuple_of_input_state_and_top_return_values(const Compile* C) const {
+ // Transparently propagate input state but parameters
+ TupleNode* tuple = TupleNode::make(
+ tf()->range(),
+ in(TypeFunc::Control),
+ in(TypeFunc::I_O),
+ in(TypeFunc::Memory),
+ in(TypeFunc::FramePtr),
+ in(TypeFunc::ReturnAdr));
+
+ // And add TOPs for the return values
+ for (uint i = TypeFunc::Parms; i < tf()->range()->cnt(); i++) {
+ tuple->set_req(i, C->top());
+ }
+
+ return tuple;
+}
+
+Node* CallLeafPureNode::Ideal(PhaseGVN* phase, bool can_reshape) {
+ if (is_dead()) {
+ return nullptr;
+ }
+
+ // We need to wait until IGVN because during parsing, usages might still be missing
+ // and we would remove the call immediately.
+ if (can_reshape && is_unused()) {
+ // The result is not used. We remove the call by replacing it with a tuple, that
+ // is later disintegrated by the projections.
+ return make_tuple_of_input_state_and_top_return_values(phase->C);
+ }
+
+ return CallRuntimeNode::Ideal(phase, can_reshape);
+}
+
#ifndef PRODUCT
void CallLeafNode::dump_spec(outputStream *st) const {
st->print("# ");
diff --git a/src/hotspot/share/opto/callnode.hpp b/src/hotspot/share/opto/callnode.hpp
index 213fbda4e89..2462a88143f 100644
--- a/src/hotspot/share/opto/callnode.hpp
+++ b/src/hotspot/share/opto/callnode.hpp
@@ -752,7 +752,7 @@ class CallNode : public SafePointNode {
// Collect all the interesting edges from a call for use in
// replacing the call by something else. Used by macro expansion
// and the late inlining support.
- void extract_projections(CallProjections* projs, bool separate_io_proj, bool do_asserts = true);
+ void extract_projections(CallProjections* projs, bool separate_io_proj, bool do_asserts = true) const;
virtual uint match_edge(uint idx) const;
@@ -928,6 +928,33 @@ class CallLeafNode : public CallRuntimeNode {
#endif
};
+/* A pure function call, they are assumed not to be safepoints, not to read or write memory,
+ * have no exception... They just take parameters, return a value without side effect. It is
+ * always correct to create some, or remove them, if the result is not used.
+ *
+ * They still have control input to allow easy lowering into other kind of calls that require
+ * a control, but this is more a technical than a moral constraint.
+ *
+ * Pure calls must have only control and data input and output: I/O, Memory and so on must be top.
+ * Nevertheless, pure calls can typically be expensive math operations so care must be taken
+ * when letting the node float.
+ */
+class CallLeafPureNode : public CallLeafNode {
+protected:
+ bool is_unused() const;
+ bool is_dead() const;
+ TupleNode* make_tuple_of_input_state_and_top_return_values(const Compile* C) const;
+
+public:
+ CallLeafPureNode(const TypeFunc* tf, address addr, const char* name,
+ const TypePtr* adr_type)
+ : CallLeafNode(tf, addr, name, adr_type) {
+ init_class_id(Class_CallLeafPure);
+ }
+ int Opcode() const override;
+ Node* Ideal(PhaseGVN* phase, bool can_reshape) override;
+};
+
//------------------------------CallLeafNoFPNode-------------------------------
// CallLeafNode, not using floating point or using it in the same manner as
// the generated code
diff --git a/src/hotspot/share/opto/classes.hpp b/src/hotspot/share/opto/classes.hpp
index bc259eed2d1..587d5fad8f2 100644
--- a/src/hotspot/share/opto/classes.hpp
+++ b/src/hotspot/share/opto/classes.hpp
@@ -61,6 +61,7 @@ macro(CallDynamicJava)
macro(CallJava)
macro(CallLeaf)
macro(CallLeafNoFP)
+macro(CallLeafPure)
macro(CallLeafVector)
macro(CallRuntime)
macro(CallStaticJava)
@@ -372,6 +373,7 @@ macro(SubI)
macro(SubL)
macro(TailCall)
macro(TailJump)
+macro(Tuple)
macro(MacroLogicV)
macro(ThreadLocal)
macro(Unlock)
diff --git a/src/hotspot/share/opto/compile.cpp b/src/hotspot/share/opto/compile.cpp
index 2b956dcb5d8..9f7f48b9a34 100644
--- a/src/hotspot/share/opto/compile.cpp
+++ b/src/hotspot/share/opto/compile.cpp
@@ -3298,6 +3298,25 @@ void Compile::final_graph_reshaping_main_switch(Node* n, Final_Reshape_Counts& f
case Op_Opaque1: // Remove Opaque Nodes before matching
n->subsume_by(n->in(1), this);
break;
+ case Op_CallLeafPure: {
+ // If the pure call is not supported, then lower to a CallLeaf.
+ if (!Matcher::match_rule_supported(Op_CallLeafPure)) {
+ CallNode* call = n->as_Call();
+ CallNode* new_call = new CallLeafNode(call->tf(), call->entry_point(),
+ call->_name, TypeRawPtr::BOTTOM);
+ new_call->init_req(TypeFunc::Control, call->in(TypeFunc::Control));
+ new_call->init_req(TypeFunc::I_O, C->top());
+ new_call->init_req(TypeFunc::Memory, C->top());
+ new_call->init_req(TypeFunc::ReturnAdr, C->top());
+ new_call->init_req(TypeFunc::FramePtr, C->top());
+ for (unsigned int i = TypeFunc::Parms; i < call->tf()->domain()->cnt(); i++) {
+ new_call->init_req(i, call->in(i));
+ }
+ n->subsume_by(new_call, this);
+ }
+ frc.inc_call_count();
+ break;
+ }
case Op_CallStaticJava:
case Op_CallJava:
case Op_CallDynamicJava:
diff --git a/src/hotspot/share/opto/divnode.cpp b/src/hotspot/share/opto/divnode.cpp
index a70194274a7..5dd8be877ff 100644
--- a/src/hotspot/share/opto/divnode.cpp
+++ b/src/hotspot/share/opto/divnode.cpp
@@ -42,19 +42,19 @@
#include <math.h>
-ModFloatingNode::ModFloatingNode(Compile* C, const TypeFunc* tf, const char* name) : CallLeafNode(tf, nullptr, name, TypeRawPtr::BOTTOM) {
+ModFloatingNode::ModFloatingNode(Compile* C, const TypeFunc* tf, address addr, const char* name) : CallLeafPureNode(tf, addr, name, TypeRawPtr::BOTTOM) {
add_flag(Flag_is_macro);
C->add_macro_node(this);
}
-ModDNode::ModDNode(Compile* C, Node* a, Node* b) : ModFloatingNode(C, OptoRuntime::Math_DD_D_Type(), "drem") {
+ModDNode::ModDNode(Compile* C, Node* a, Node* b) : ModFloatingNode(C, OptoRuntime::Math_DD_D_Type(), CAST_FROM_FN_PTR(address, SharedRuntime::drem), "drem") {
init_req(TypeFunc::Parms + 0, a);
init_req(TypeFunc::Parms + 1, C->top());
init_req(TypeFunc::Parms + 2, b);
init_req(TypeFunc::Parms + 3, C->top());
}
-ModFNode::ModFNode(Compile* C, Node* a, Node* b) : ModFloatingNode(C, OptoRuntime::modf_Type(), "frem") {
+ModFNode::ModFNode(Compile* C, Node* a, Node* b) : ModFloatingNode(C, OptoRuntime::modf_Type(), CAST_FROM_FN_PTR(address, SharedRuntime::frem), "frem") {
init_req(TypeFunc::Parms + 0, a);
init_req(TypeFunc::Parms + 1, b);
}
@@ -1516,137 +1516,109 @@ const Type* UModLNode::Value(PhaseGVN* phase) const {
return unsigned_mod_value<TypeLong, julong, jlong>(phase, this);
}
-Node* ModFNode::Ideal(PhaseGVN* phase, bool can_reshape) {
- if (!can_reshape) {
- return nullptr;
- }
- PhaseIterGVN* igvn = phase->is_IterGVN();
-
- bool result_is_unused = proj_out_or_null(TypeFunc::Parms) == nullptr;
- bool not_dead = proj_out_or_null(TypeFunc::Control) != nullptr;
- if (result_is_unused && not_dead) {
- return replace_with_con(igvn, TypeF::make(0.));
- }
-
- // Either input is TOP ==> the result is TOP
- const Type* t1 = phase->type(dividend());
- const Type* t2 = phase->type(divisor());
- if (t1 == Type::TOP || t2 == Type::TOP) {
- return phase->C->top();
- }
-
+const Type* ModFNode::get_result_if_constant(const Type* dividend, const Type* divisor) const {
// If either number is not a constant, we know nothing.
- if ((t1->base() != Type::FloatCon) || (t2->base() != Type::FloatCon)) {
+ if ((dividend->base() != Type::FloatCon) || (divisor->base() != Type::FloatCon)) {
return nullptr; // note: x%x can be either NaN or 0
}
- float f1 = t1->getf();
- float f2 = t2->getf();
- jint x1 = jint_cast(f1); // note: *(int*)&f1, not just (int)f1
- jint x2 = jint_cast(f2);
+ float dividend_f = dividend->getf();
+ float divisor_f = divisor->getf();
+ jint dividend_i = jint_cast(dividend_f); // note: *(int*)&f1, not just (int)f1
+ jint divisor_i = jint_cast(divisor_f);
// If either is a NaN, return an input NaN
- if (g_isnan(f1)) {
- return replace_with_con(igvn, t1);
+ if (g_isnan(dividend_f)) {
+ return dividend;
}
- if (g_isnan(f2)) {
- return replace_with_con(igvn, t2);
+ if (g_isnan(divisor_f)) {
+ return divisor;
}
// If an operand is infinity or the divisor is +/- zero, punt.
- if (!g_isfinite(f1) || !g_isfinite(f2) || x2 == 0 || x2 == min_jint) {
+ if (!g_isfinite(dividend_f) || !g_isfinite(divisor_f) || divisor_i == 0 || divisor_i == min_jint) {
return nullptr;
}
// We must be modulo'ing 2 float constants.
// Make sure that the sign of the fmod is equal to the sign of the dividend
- jint xr = jint_cast(fmod(f1, f2));
- if ((x1 ^ xr) < 0) {
+ jint xr = jint_cast(fmod(dividend_f, divisor_f));
+ if ((dividend_i ^ xr) < 0) {
xr ^= min_jint;
}
- return replace_with_con(igvn, TypeF::make(jfloat_cast(xr)));
+ return TypeF::make(jfloat_cast(xr));
}
-Node* ModDNode::Ideal(PhaseGVN* phase, bool can_reshape) {
- if (!can_reshape) {
- return nullptr;
- }
- PhaseIterGVN* igvn = phase->is_IterGVN();
-
- bool result_is_unused = proj_out_or_null(TypeFunc::Parms) == nullptr;
- bool not_dead = proj_out_or_null(TypeFunc::Control) != nullptr;
- if (result_is_unused && not_dead) {
- return replace_with_con(igvn, TypeD::make(0.));
- }
-
- // Either input is TOP ==> the result is TOP
- const Type* t1 = phase->type(dividend());
- const Type* t2 = phase->type(divisor());
- if (t1 == Type::TOP || t2 == Type::TOP) {
- return nullptr;
- }
-
+const Type* ModDNode::get_result_if_constant(const Type* dividend, const Type* divisor) const {
// If either number is not a constant, we know nothing.
- if ((t1->base() != Type::DoubleCon) || (t2->base() != Type::DoubleCon)) {
+ if ((dividend->base() != Type::DoubleCon) || (divisor->base() != Type::DoubleCon)) {
return nullptr; // note: x%x can be either NaN or 0
}
- double f1 = t1->getd();
- double f2 = t2->getd();
- jlong x1 = jlong_cast(f1); // note: *(long*)&f1, not just (long)f1
- jlong x2 = jlong_cast(f2);
+ double dividend_d = dividend->getd();
+ double divisor_d = divisor->getd();
+ jlong dividend_l = jlong_cast(dividend_d); // note: *(long*)&f1, not just (long)f1
+ jlong divisor_l = jlong_cast(divisor_d);
// If either is a NaN, return an input NaN
- if (g_isnan(f1)) {
- return replace_with_con(igvn, t1);
+ if (g_isnan(dividend_d)) {
+ return dividend;
}
- if (g_isnan(f2)) {
- return replace_with_con(igvn, t2);
+ if (g_isnan(divisor_d)) {
+ return divisor;
}
// If an operand is infinity or the divisor is +/- zero, punt.
- if (!g_isfinite(f1) || !g_isfinite(f2) || x2 == 0 || x2 == min_jlong) {
+ if (!g_isfinite(dividend_d) || !g_isfinite(divisor_d) || divisor_l == 0 || divisor_l == min_jlong) {
return nullptr;
}
// We must be modulo'ing 2 double constants.
// Make sure that the sign of the fmod is equal to the sign of the dividend
- jlong xr = jlong_cast(fmod(f1, f2));
- if ((x1 ^ xr) < 0) {
+ jlong xr = jlong_cast(fmod(dividend_d, divisor_d));
+ if ((dividend_l ^ xr) < 0) {
xr ^= min_jlong;
}
- return replace_with_con(igvn, TypeD::make(jdouble_cast(xr)));
+ return TypeD::make(jdouble_cast(xr));
}
-Node* ModFloatingNode::replace_with_con(PhaseIterGVN* phase, const Type* con) {
- Compile* C = phase->C;
- Node* con_node = phase->makecon(con);
- CallProjections projs;
- extract_projections(&projs, false, false);
- phase->replace_node(projs.fallthrough_proj, in(TypeFunc::Control));
- if (projs.fallthrough_catchproj != nullptr) {
- phase->replace_node(projs.fallthrough_catchproj, in(TypeFunc::Control));
- }
- if (projs.fallthrough_memproj != nullptr) {
- phase->replace_node(projs.fallthrough_memproj, in(TypeFunc::Memory));
- }
- if (projs.catchall_memproj != nullptr) {
- phase->replace_node(projs.catchall_memproj, C->top());
- }
- if (projs.fallthrough_ioproj != nullptr) {
- phase->replace_node(projs.fallthrough_ioproj, in(TypeFunc::I_O));
- }
- assert(projs.catchall_ioproj == nullptr, "no exceptions from floating mod");
- assert(projs.catchall_catchproj == nullptr, "no exceptions from floating mod");
- if (projs.resproj != nullptr) {
- phase->replace_node(projs.resproj, con_node);
+Node* ModFloatingNode::Ideal(PhaseGVN* phase, bool can_reshape) {
+ if (can_reshape) {
+ PhaseIterGVN* igvn = phase->is_IterGVN();
+
+ // Either input is TOP ==> the result is TOP
+ const Type* dividend_type = phase->type(dividend());
+ const Type* divisor_type = phase->type(divisor());
+ if (dividend_type == Type::TOP || divisor_type == Type::TOP) {
+ return phase->C->top();
+ }
+ const Type* constant_result = get_result_if_constant(dividend_type, divisor_type);
+ if (constant_result != nullptr) {
+ return make_tuple_of_input_state_and_constant_result(igvn, constant_result);
+ }
}
- phase->replace_node(this, C->top());
- C->remove_macro_node(this);
- disconnect_inputs(C);
- return nullptr;
+
+ return CallLeafPureNode::Ideal(phase, can_reshape);
+}
+
+/* Give a tuple node for ::Ideal to return, made of the input state (control to return addr)
+ * and the given constant result. Idealization of projections will make sure to transparently
+ * propagate the input state and replace the result by the said constant.
+ */
+TupleNode* ModFloatingNode::make_tuple_of_input_state_and_constant_result(PhaseIterGVN* phase, const Type* con) const {
+ Node* con_node = phase->makecon(con);
+ TupleNode* tuple = TupleNode::make(
+ tf()->range(),
+ in(TypeFunc::Control),
+ in(TypeFunc::I_O),
+ in(TypeFunc::Memory),
+ in(TypeFunc::FramePtr),
+ in(TypeFunc::ReturnAdr),
+ con_node);
+
+ return tuple;
}
//=============================================================================
diff --git a/src/hotspot/share/opto/divnode.hpp b/src/hotspot/share/opto/divnode.hpp
index 127e2431b0b..b13460c89f5 100644
--- a/src/hotspot/share/opto/divnode.hpp
+++ b/src/hotspot/share/opto/divnode.hpp
@@ -156,40 +156,45 @@ class ModLNode : public Node {
};
// Base class for float and double modulus
-class ModFloatingNode : public CallLeafNode {
+class ModFloatingNode : public CallLeafPureNode {
+ TupleNode* make_tuple_of_input_state_and_constant_result(PhaseIterGVN* phase, const Type* con) const;
+
protected:
- Node* replace_with_con(PhaseIterGVN* phase, const Type* con);
+ virtual Node* dividend() const = 0;
+ virtual Node* divisor() const = 0;
+ virtual const Type* get_result_if_constant(const Type* dividend, const Type* divisor) const = 0;
public:
- ModFloatingNode(Compile* C, const TypeFunc* tf, const char *name);
+ ModFloatingNode(Compile* C, const TypeFunc* tf, address addr, const char* name);
+ Node* Ideal(PhaseGVN* phase, bool can_reshape) override;
};
// Float Modulus
class ModFNode : public ModFloatingNode {
private:
- Node* dividend() const { return in(TypeFunc::Parms + 0); }
- Node* divisor() const { return in(TypeFunc::Parms + 1); }
+ Node* dividend() const override { return in(TypeFunc::Parms + 0); }
+ Node* divisor() const override { return in(TypeFunc::Parms + 1); }
+ const Type* get_result_if_constant(const Type* dividend, const Type* divisor) const override;
public:
ModFNode(Compile* C, Node* a, Node* b);
- virtual int Opcode() const;
- virtual uint ideal_reg() const { return Op_RegF; }
- virtual uint size_of() const { return sizeof(*this); }
- virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
+ int Opcode() const override;
+ uint ideal_reg() const override { return Op_RegF; }
+ uint size_of() const override { return sizeof(*this); }
};
// Double Modulus
class ModDNode : public ModFloatingNode {
private:
- Node* dividend() const { return in(TypeFunc::Parms + 0); }
- Node* divisor() const { return in(TypeFunc::Parms + 2); }
+ Node* dividend() const override { return in(TypeFunc::Parms + 0); }
+ Node* divisor() const override { return in(TypeFunc::Parms + 2); }
+ const Type* get_result_if_constant(const Type* dividend, const Type* divisor) const override;
public:
ModDNode(Compile* C, Node* a, Node* b);
- virtual int Opcode() const;
- virtual uint ideal_reg() const { return Op_RegD; }
- virtual uint size_of() const { return sizeof(*this); }
- virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
+ int Opcode() const override;
+ uint ideal_reg() const override { return Op_RegD; }
+ uint size_of() const override { return sizeof(*this); }
};
//------------------------------UModINode---------------------------------------
diff --git a/src/hotspot/share/opto/graphKit.cpp b/src/hotspot/share/opto/graphKit.cpp
index 20feca26ede..1b8b7008578 100644
--- a/src/hotspot/share/opto/graphKit.cpp
+++ b/src/hotspot/share/opto/graphKit.cpp
@@ -1880,14 +1880,20 @@ Node* GraphKit::set_results_for_java_call(CallJavaNode* call, bool separate_io_p
// after the call, if this call has restricted memory effects.
Node* GraphKit::set_predefined_input_for_runtime_call(SafePointNode* call, Node* narrow_mem) {
// Set fixed predefined input arguments
- Node* memory = reset_memory();
- Node* m = narrow_mem == nullptr ? memory : narrow_mem;
- call->init_req( TypeFunc::Control, control() );
- call->init_req( TypeFunc::I_O, top() ); // does no i/o
- call->init_req( TypeFunc::Memory, m ); // may gc ptrs
- call->init_req( TypeFunc::FramePtr, frameptr() );
- call->init_req( TypeFunc::ReturnAdr, top() );
- return memory;
+ call->init_req(TypeFunc::Control, control());
+ call->init_req(TypeFunc::I_O, top()); // does no i/o
+ call->init_req(TypeFunc::ReturnAdr, top());
+ if (call->is_CallLeafPure()) {
+ call->init_req(TypeFunc::Memory, top());
+ call->init_req(TypeFunc::FramePtr, top());
+ return nullptr;
+ } else {
+ Node* memory = reset_memory();
+ Node* m = narrow_mem == nullptr ? memory : narrow_mem;
+ call->init_req(TypeFunc::Memory, m); // may gc ptrs
+ call->init_req(TypeFunc::FramePtr, frameptr());
+ return memory;
+ }
}
//-------------------set_predefined_output_for_runtime_call--------------------
@@ -1905,6 +1911,11 @@ void GraphKit::set_predefined_output_for_runtime_call(Node* call,
const TypePtr* hook_mem) {
// no i/o
set_control(_gvn.transform( new ProjNode(call,TypeFunc::Control) ));
+ if (call->is_CallLeafPure()) {
+ // Pure function have only control (for now) and data output, in particular
+ // they don't touch the memory, so we don't want a memory proj that is set after.
+ return;
+ }
if (keep_mem) {
// First clone the existing memory state
set_all_memory(keep_mem);
@@ -2491,6 +2502,8 @@ Node* GraphKit::make_runtime_call(int flags,
} else if (flags & RC_VECTOR){
uint num_bits = call_type->range()->field_at(TypeFunc::Parms)->is_vect()->length_in_bytes() * BitsPerByte;
call = new CallLeafVectorNode(call_type, call_addr, call_name, adr_type, num_bits);
+ } else if (flags & RC_PURE) {
+ call = new CallLeafPureNode(call_type, call_addr, call_name, adr_type);
} else {
call = new CallLeafNode(call_type, call_addr, call_name, adr_type);
}
diff --git a/src/hotspot/share/opto/graphKit.hpp b/src/hotspot/share/opto/graphKit.hpp
index 28773d75333..806a211d7e2 100644
--- a/src/hotspot/share/opto/graphKit.hpp
+++ b/src/hotspot/share/opto/graphKit.hpp
@@ -784,6 +784,7 @@ class GraphKit : public Phase {
RC_NARROW_MEM = 16, // input memory is same as output
RC_UNCOMMON = 32, // freq. expected to be like uncommon trap
RC_VECTOR = 64, // CallLeafVectorNode
+ RC_PURE = 128, // CallLeaf is pure
RC_LEAF = 0 // null value: no flags set
};
diff --git a/src/hotspot/share/opto/library_call.cpp b/src/hotspot/share/opto/library_call.cpp
index f74af38387c..12960d101a8 100644
--- a/src/hotspot/share/opto/library_call.cpp
+++ b/src/hotspot/share/opto/library_call.cpp
@@ -1802,7 +1802,7 @@ bool LibraryCallKit::runtime_math(const TypeFunc* call_type, address funcAddr, c
Node* b = (call_type == OptoRuntime::Math_DD_D_Type()) ? argument(2) : nullptr;
const TypePtr* no_memory_effects = nullptr;
- Node* trig = make_runtime_call(RC_LEAF, call_type, funcAddr, funcName,
+ Node* trig = make_runtime_call(RC_LEAF | RC_PURE, call_type, funcAddr, funcName,
no_memory_effects,
a, top(), b, b ? top() : nullptr);
Node* value = _gvn.transform(new ProjNode(trig, TypeFunc::Parms+0));
diff --git a/src/hotspot/share/opto/macro.cpp b/src/hotspot/share/opto/macro.cpp
index acf1dbabf19..aafc5d3c170 100644
--- a/src/hotspot/share/opto/macro.cpp
+++ b/src/hotspot/share/opto/macro.cpp
@@ -2638,17 +2638,14 @@ bool PhaseMacroExpand::expand_macro_nodes() {
switch (n->Opcode()) {
case Op_ModD:
case Op_ModF: {
- bool is_drem = n->Opcode() == Op_ModD;
CallNode* mod_macro = n->as_Call();
- CallNode* call = new CallLeafNode(mod_macro->tf(),
- is_drem ? CAST_FROM_FN_PTR(address, SharedRuntime::drem)
- : CAST_FROM_FN_PTR(address, SharedRuntime::frem),
- is_drem ? "drem" : "frem", TypeRawPtr::BOTTOM);
+ CallNode* call = new CallLeafPureNode(mod_macro->tf(), mod_macro->entry_point(),
+ mod_macro->_name, TypeRawPtr::BOTTOM);
call->init_req(TypeFunc::Control, mod_macro->in(TypeFunc::Control));
- call->init_req(TypeFunc::I_O, mod_macro->in(TypeFunc::I_O));
- call->init_req(TypeFunc::Memory, mod_macro->in(TypeFunc::Memory));
- call->init_req(TypeFunc::ReturnAdr, mod_macro->in(TypeFunc::ReturnAdr));
- call->init_req(TypeFunc::FramePtr, mod_macro->in(TypeFunc::FramePtr));
+ call->init_req(TypeFunc::I_O, C->top());
+ call->init_req(TypeFunc::Memory, C->top());
+ call->init_req(TypeFunc::ReturnAdr, C->top());
+ call->init_req(TypeFunc::FramePtr, C->top());
for (unsigned int i = 0; i < mod_macro->tf()->domain()->cnt() - TypeFunc::Parms; i++) {
call->init_req(TypeFunc::Parms + i, mod_macro->in(TypeFunc::Parms + i));
}
diff --git a/src/hotspot/share/opto/multnode.cpp b/src/hotspot/share/opto/multnode.cpp
index 736e84315ee..f429d5daac0 100644
--- a/src/hotspot/share/opto/multnode.cpp
+++ b/src/hotspot/share/opto/multnode.cpp
@@ -120,6 +120,10 @@ const TypePtr *ProjNode::adr_type() const {
if (bottom_type() == Type::MEMORY) {
// in(0) might be a narrow MemBar; otherwise we will report TypePtr::BOTTOM
Node* ctrl = in(0);
+ if (ctrl->Opcode() == Op_Tuple) {
+ // Jumping over Tuples: the i-th projection of a Tuple is the i-th input of the Tuple.
+ ctrl = ctrl->in(_con);
+ }
if (ctrl == nullptr) return nullptr; // node is dead
const TypePtr* adr_type = ctrl->adr_type();
#ifdef ASSERT
@@ -163,6 +167,15 @@ void ProjNode::check_con() const {
assert(_con < t->is_tuple()->cnt(), "ProjNode::_con must be in range");
}
+//------------------------------Identity---------------------------------------
+Node* ProjNode::Identity(PhaseGVN* phase) {
+ if (in(0) != nullptr && in(0)->Opcode() == Op_Tuple) {
+ // Jumping over Tuples: the i-th projection of a Tuple is the i-th input of the Tuple.
+ return in(0)->in(_con);
+ }
+ return this;
+}
+
//------------------------------Value------------------------------------------
const Type* ProjNode::Value(PhaseGVN* phase) const {
if (in(0) == nullptr) return Type::TOP;
diff --git a/src/hotspot/share/opto/multnode.hpp b/src/hotspot/share/opto/multnode.hpp
index dff2caed38d..834dcfdca6d 100644
--- a/src/hotspot/share/opto/multnode.hpp
+++ b/src/hotspot/share/opto/multnode.hpp
@@ -82,6 +82,7 @@ class ProjNode : public Node {
virtual const Type *bottom_type() const;
virtual const TypePtr *adr_type() const;
virtual bool pinned() const;
+ virtual Node* Identity(PhaseGVN* phase);
virtual const Type* Value(PhaseGVN* phase) const;
virtual uint ideal_reg() const;
virtual const RegMask &out_RegMask() const;
@@ -105,4 +106,49 @@ class ProjNode : public Node {
ProjNode* other_if_proj() const;
};
+/* Tuples are used to avoid manual graph surgery. When a node with Proj outputs (such as a call)
+ * must be removed and its ouputs replaced by its input, or some other value, we can make its
+ * ::Ideal return a tuple of what we want for each output: the ::Identity of output Proj will
+ * take care to jump over the Tuple and directly pick up the right input of the Tuple.
+ *
+ * For instance, if a function call is proven to have no side effect and return the constant 0,
+ * we can replace it with the 6-tuple:
+ * (control input, IO input, memory input, frame ptr input, return addr input, Con:0)
+ * all the output projections will pick up the input of the now gone call, except for the result
+ * projection that is replaced by 0.
+ *
+ * Using TupleNode avoid manual graph surgery and leave that to our expert surgeon: IGVN.
+ * Since the user of a Tuple are expected to be Proj, when creating a tuple during idealization,
+ * the output Proj should be enqueued for IGVN immediately after, and the tuple should not survive
+ * after the current IGVN.
+ */
+class TupleNode : public MultiNode {
+ const TypeTuple* _tf;
+
+ template <typename... NN>
+ static void make_helper(TupleNode* tn, uint i, Node* node, NN... nn) {
+ tn->set_req(i, node);
+ make_helper(tn, i + 1, nn...);
+ }
+
+ static void make_helper(TupleNode*, uint) {}
+
+public:
+ TupleNode(const TypeTuple* tf) : MultiNode(tf->cnt()), _tf(tf) {}
+
+ int Opcode() const override;
+ const Type* bottom_type() const override { return _tf; }
+
+ /* Give as many `Node*` as you want in the `nn` pack:
+ * TupleNode::make(tf, input1)
+ * TupleNode::make(tf, input1, input2, input3, input4)
+ */
+ template <typename... NN>
+ static TupleNode* make(const TypeTuple* tf, NN... nn) {
+ TupleNode* tn = new TupleNode(tf);
+ make_helper(tn, 0, nn...);
+ return tn;
+ }
+};
+
#endif // SHARE_OPTO_MULTNODE_HPP
diff --git a/src/hotspot/share/opto/node.cpp b/src/hotspot/share/opto/node.cpp
index 8f6c67c16f5..5ecc038954d 100644
--- a/src/hotspot/share/opto/node.cpp
+++ b/src/hotspot/share/opto/node.cpp
@@ -2946,23 +2946,13 @@ bool Node::is_dead_loop_safe() const {
bool Node::is_div_or_mod(BasicType bt) const { return Opcode() == Op_Div(bt) || Opcode() == Op_Mod(bt) ||
Opcode() == Op_UDiv(bt) || Opcode() == Op_UMod(bt); }
-bool Node::is_pure_function() const {
- switch (Opcode()) {
- case Op_ModD:
- case Op_ModF:
- return true;
- default:
- return false;
- }
-}
-
// `maybe_pure_function` is assumed to be the input of `this`. This is a bit redundant,
// but we already have and need maybe_pure_function in all the call sites, so
// it makes it obvious that the `maybe_pure_function` is the same node as in the caller,
// while it takes more thinking to realize that a locally computed in(0) must be equal to
// the local in the caller.
bool Node::is_data_proj_of_pure_function(const Node* maybe_pure_function) const {
- return Opcode() == Op_Proj && as_Proj()->_con == TypeFunc::Parms && maybe_pure_function->is_pure_function();
+ return Opcode() == Op_Proj && as_Proj()->_con == TypeFunc::Parms && maybe_pure_function->is_CallLeafPure();
}
//=============================================================================
diff --git a/src/hotspot/share/opto/node.hpp b/src/hotspot/share/opto/node.hpp
index 2bbb10879f5..dc0ac474c4b 100644
--- a/src/hotspot/share/opto/node.hpp
+++ b/src/hotspot/share/opto/node.hpp
@@ -54,6 +54,7 @@ class CallDynamicJavaNode;
class CallJavaNode;
class CallLeafNode;
class CallLeafNoFPNode;
+class CallLeafPureNode;
class CallNode;
class CallRuntimeNode;
class CallStaticJavaNode;
@@ -673,6 +674,7 @@ class Node {
DEFINE_CLASS_ID(CallRuntime, Call, 1)
DEFINE_CLASS_ID(CallLeaf, CallRuntime, 0)
DEFINE_CLASS_ID(CallLeafNoFP, CallLeaf, 0)
+ DEFINE_CLASS_ID(CallLeafPure, CallLeaf, 1)
DEFINE_CLASS_ID(Allocate, Call, 2)
DEFINE_CLASS_ID(AllocateArray, Allocate, 0)
DEFINE_CLASS_ID(AbstractLock, Call, 3)
@@ -907,6 +909,7 @@ class Node {
DEFINE_CLASS_QUERY(CallJava)
DEFINE_CLASS_QUERY(CallLeaf)
DEFINE_CLASS_QUERY(CallLeafNoFP)
+ DEFINE_CLASS_QUERY(CallLeafPure)
DEFINE_CLASS_QUERY(CallRuntime)
DEFINE_CLASS_QUERY(CallStaticJava)
DEFINE_CLASS_QUERY(Catch)
@@ -1289,8 +1292,6 @@ class Node {
bool is_div_or_mod(BasicType bt) const;
- bool is_pure_function() const;
-
bool is_data_proj_of_pure_function(const Node* maybe_pure_function) const;
//----------------- Printing, etc
diff --git a/src/hotspot/share/opto/parse2.cpp b/src/hotspot/share/opto/parse2.cpp
index 1a4c3c91c4f..04b6e49b620 100644
--- a/src/hotspot/share/opto/parse2.cpp
+++ b/src/hotspot/share/opto/parse2.cpp
@@ -1097,11 +1097,11 @@ void Parse::jump_switch_ranges(Node* key_val, SwitchRange *lo, SwitchRange *hi,
Node* Parse::floating_point_mod(Node* a, Node* b, BasicType type) {
assert(type == BasicType::T_FLOAT || type == BasicType::T_DOUBLE, "only float and double are floating points");
- CallNode* mod = type == BasicType::T_DOUBLE ? static_cast<CallNode*>(new ModDNode(C, a, b)) : new ModFNode(C, a, b);
+ CallLeafPureNode* mod = type == BasicType::T_DOUBLE ? static_cast<CallLeafPureNode*>(new ModDNode(C, a, b)) : new ModFNode(C, a, b);
- Node* prev_mem = set_predefined_input_for_runtime_call(mod);
- mod = _gvn.transform(mod)->as_Call();
- set_predefined_output_for_runtime_call(mod, prev_mem, TypeRawPtr::BOTTOM);
+ set_predefined_input_for_runtime_call(mod);
+ mod = _gvn.transform(mod)->as_CallLeafPure();
+ set_predefined_output_for_runtime_call(mod);
Node* result = _gvn.transform(new ProjNode(mod, TypeFunc::Parms + 0));
record_for_igvn(mod);
return result;
--
2.53.0
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