From 968e6524fc1ace9c08caba67fb3784018afa3a16 Mon Sep 17 00:00:00 2001
From: Gita Koblents <koblents@ca.ibm.com>
Date: Mon, 31 Oct 2022 21:29:30 -0400
Subject: [PATCH] Inline jdk/internal/util/Preconditions.checkIndex

- this method contains a simple check whether provided index is greater
  than 0 and less than provided upper bound. This check lands itself
  well to various JIT optimizations (e.g. moving out of a loop).
---
 runtime/compiler/codegen/J9RecognizedMethodsEnum.hpp |  1 +
 runtime/compiler/env/j9method.cpp                    | 10 ++++++++++
 runtime/compiler/optimizer/InlinerTempForJ9.cpp      |  2 ++
 3 files changed, 13 insertions(+)

diff --git a/runtime/compiler/codegen/J9RecognizedMethodsEnum.hpp b/runtime/compiler/codegen/J9RecognizedMethodsEnum.hpp
index 7c5d788ff0f..d3bffdc87f1 100644
--- a/runtime/compiler/codegen/J9RecognizedMethodsEnum.hpp
+++ b/runtime/compiler/codegen/J9RecognizedMethodsEnum.hpp
@@ -445,6 +445,7 @@
 
    jdk_internal_misc_Unsafe_copyMemory0,
    jdk_internal_loader_NativeLibraries_load,
+   jdk_internal_util_Preconditions_checkIndex,
 
    FirstVectorMethod,
    jdk_internal_vm_vector_VectorSupport_load = FirstVectorMethod,
diff --git a/runtime/compiler/env/j9method.cpp b/runtime/compiler/env/j9method.cpp
index fe013912811..19b45a52190 100644
--- a/runtime/compiler/env/j9method.cpp
+++ b/runtime/compiler/env/j9method.cpp
@@ -2988,6 +2988,14 @@ void TR_ResolvedJ9Method::construct()
       };
 #endif /* JAVA_SPEC_VERSION >= 15 */
 
+
+   static X PreconditionsMethods[] =
+      {
+      {x(TR::jdk_internal_util_Preconditions_checkIndex, "checkIndex", "(IILjava/util/function/BiFunction;)I")},
+      {  TR::unknownMethod}
+      };
+
+
    static X VectorSupportMethods[] =
       {
       {x(TR::jdk_internal_vm_vector_VectorSupport_load, "load", "(Ljava/lang/Class;Ljava/lang/Class;ILjava/lang/Object;JLjava/lang/Object;JLjdk/internal/vm/vector/VectorSupport$VectorSpecies;Ljdk/internal/vm/vector/VectorSupport$LoadOperation;)Ljdk/internal/vm/vector/VectorSupport$VectorPayload;")},
@@ -4079,6 +4087,8 @@ void TR_ResolvedJ9Method::construct()
       {
       { "com/ibm/jit/DecimalFormatHelper", DecimalFormatHelperMethods},
       { "jdk/internal/reflect/Reflection", ReflectionMethods },
+      { "jdk/internal/util/Preconditions", PreconditionsMethods },
+
       { 0 }
       };
    static Y class32[] =
diff --git a/runtime/compiler/optimizer/InlinerTempForJ9.cpp b/runtime/compiler/optimizer/InlinerTempForJ9.cpp
index 5e9477443d2..37b849cf8f5 100644
--- a/runtime/compiler/optimizer/InlinerTempForJ9.cpp
+++ b/runtime/compiler/optimizer/InlinerTempForJ9.cpp
@@ -356,6 +356,8 @@ TR_J9InlinerPolicy::alwaysWorthInlining(TR_ResolvedMethod * calleeMethod, TR::No
       case TR::java_lang_String_regionMatchesInternal:
       case TR::java_lang_String_regionMatches:
       case TR::java_lang_Class_newInstance:
+      case TR::jdk_internal_util_Preconditions_checkIndex:
+
       // we rely on inlining compareAndSwap so we see the inner native call and can special case it
       case TR::com_ibm_jit_JITHelpers_compareAndSwapIntInObject:
       case TR::com_ibm_jit_JITHelpers_compareAndSwapLongInObject: