Accelerate vectorizedMismatch in IL

This patch adds ArraysSupport.vectorizedMismatch as a recognized method, and adds a SupportsInlineVectorizedMismatch flag to the code generator. This flag is set in Z, Power, aarch64 and x86 code generator initialization if the arraycmp opcode is supported and the TR_disableInlineVectorizedMismatch environment variable is not set. If the flag is set, vectorizedMismatch call nodes are transformed to a functionally equivalent tree that uses arraycmp. Fixes: #15204 Signed-off-by: Spencer Comin <[email protected]>
eclipse-openj9 · Oct 25, 2023 · 0636989 · 0636989
1 parent 06c3abc
commit 0636989
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diff --git a/runtime/compiler/aarch64/codegen/J9CodeGenerator.cpp b/runtime/compiler/aarch64/codegen/J9CodeGenerator.cpp
@@ -77,6 +77,12 @@ J9::ARM64::CodeGenerator::initialize()
       comp->setOption(TR_EnableMonitorCacheLookup);
       }
 
+   static bool disableInlineVectorizedMismatch = feGetEnv("TR_disableInlineVectorizedMismatch") != NULL;
+   if (cg->getSupportsArrayCmpLen() && !disableInlineVectorizedMismatch)
+      {
+      cg->setSupportsInlineVectorizedMismatch();
+      }
+
    if (comp->fej9()->hasFixedFrameC_CallingConvention())
       cg->setHasFixedFrameC_CallingConvention();
    }

diff --git a/runtime/compiler/codegen/J9CodeGenerator.hpp b/runtime/compiler/codegen/J9CodeGenerator.hpp
@@ -492,6 +492,16 @@ void addMonClass(TR::Node* monNode, TR_OpaqueClassBlock* clazz);
 	*/
    void setSupportsInlineEncodeASCII() { _j9Flags.set(SupportsInlineEncodeASCII); }
 
+   /** \brief
+   *   Determines whether the code generator supports inlining of jdk/internal/util/ArraysSupport.vectorizedMismatch
+   */
+   bool getSupportsInlineVectorizedMismatch() { return _j9Flags.testAny(SupportsInlineVectorizedMismatch); }
+
+   /** \brief
+   *   The code generator supports inlining of jdk/internal/util/ArraysSupport.vectorizedMismatch
+   */
+   void setSupportsInlineVectorizedMismatch() { _j9Flags.set(SupportsInlineVectorizedMismatch); }
+
    /**
     * \brief
     *    The number of nodes between a monext and the next monent before
@@ -649,6 +659,7 @@ void addMonClass(TR::Node* monNode, TR_OpaqueClassBlock* clazz);
       SupportsIntegerToChars                              = 0x00000200,
       SupportsInlineEncodeASCII                           = 0x00000400,
       SavesNonVolatileGPRsForGC                           = 0x00000800,
+      SupportsInlineVectorizedMismatch                    = 0x00001000,
       };
 
    flags32_t _j9Flags;

diff --git a/runtime/compiler/codegen/J9RecognizedMethodsEnum.hpp b/runtime/compiler/codegen/J9RecognizedMethodsEnum.hpp
@@ -433,6 +433,7 @@
 
    jdk_internal_misc_Unsafe_copyMemory0,
    jdk_internal_loader_NativeLibraries_load,
+   jdk_internal_util_ArraysSupport_vectorizedMismatch,
    jdk_internal_util_Preconditions_checkIndex,
 
    FirstVectorMethod,

diff --git a/runtime/compiler/env/j9method.cpp b/runtime/compiler/env/j9method.cpp
@@ -3970,6 +3970,12 @@ void TR_ResolvedJ9Method::construct()
       {  TR::unknownMethod},
       };
 
+   static X ArraysSupportMethods [] =
+      {
+      {x(TR::jdk_internal_util_ArraysSupport_vectorizedMismatch, "vectorizedMismatch", "(Ljava/lang/Object;JLjava/lang/Object;JII)I")},
+      {  TR::unknownMethod}
+      };
+
    struct Y { const char * _class; X * _methods; };
 
    /* classXX where XX is the number of characters in the class name */
@@ -4151,7 +4157,7 @@ void TR_ResolvedJ9Method::construct()
       { "com/ibm/jit/DecimalFormatHelper", DecimalFormatHelperMethods},
       { "jdk/internal/reflect/Reflection", ReflectionMethods },
       { "jdk/internal/util/Preconditions", PreconditionsMethods },
-
+      { "jdk/internal/util/ArraysSupport", ArraysSupportMethods },
       { 0 }
       };
    static Y class32[] =

diff --git a/runtime/compiler/optimizer/J9RecognizedCallTransformer.cpp b/runtime/compiler/optimizer/J9RecognizedCallTransformer.cpp
@@ -334,6 +334,60 @@ void J9::RecognizedCallTransformer::process_java_lang_StringUTF16_toBytes(TR::Tr
       }
    }
 
+void J9::RecognizedCallTransformer::process_jdk_internal_util_ArraysSupport_vectorizedMismatch(TR::TreeTop* treetop, TR::Node* node)
+   {
+   TR::Node* a = node->getChild(0);
+   TR::Node* aOffset = node->getChild(1);
+   TR::Node* b = node->getChild(2);
+   TR::Node* bOffset = node->getChild(3);
+   TR::Node* length = node->getChild(4);
+   TR::Node* log2ArrayIndexScale = node->getChild(5);
+   TR::Node* log2ArrayIndexScale64Bits = TR::Node::create(node, TR::iu2l, 1, log2ArrayIndexScale);
+
+   TR::Node* lengthInBytes = TR::Node::create(node, TR::lshl, 2,
+      TR::Node::create(node, TR::iu2l, 1, length),
+      log2ArrayIndexScale);
+
+   TR::Node* mask = TR::Node::create(node, TR::lor, 2,
+      TR::Node::create(node, TR::lshl, 2,
+         log2ArrayIndexScale64Bits,
+         TR::Node::iconst(node, 1)),
+      TR::Node::lconst(node, 3));
+
+   TR::Node* lengthToCompare = TR::Node::create(node, TR::land, 2,
+      lengthInBytes,
+      TR::Node::create(node, TR::lxor, 2, mask, TR::Node::lconst(node, -1)));
+
+   TR::Node* mismatchByteIndex = TR::Node::create(node, TR::arraycmplen, 3);
+   // TODO: replace the following aladd's with generateDataAddrLoadTrees when off-heap memory changes come in
+   // See OpenJ9 issue #16717 https://github.com/eclipse-openj9/openj9/issues/16717
+   mismatchByteIndex->setAndIncChild(0, TR::Node::create(node, TR::aladd, 2, a, aOffset));
+   mismatchByteIndex->setAndIncChild(1, TR::Node::create(node, TR::aladd, 2, b, bOffset));
+   mismatchByteIndex->setAndIncChild(2, lengthToCompare);
+   mismatchByteIndex->setSymbolReference(getSymRefTab()->findOrCreateArrayCmpLenSymbol());
+
+   TR::Node* invertedRemainder = TR::Node::create(node, TR::ixor, 2,
+      TR::Node::create(node, TR::l2i, 1,
+         TR::Node::create(node, TR::lshr, 2,
+            TR::Node::create(node, TR::land, 2, lengthInBytes, mask),
+            log2ArrayIndexScale)),
+      TR::Node::iconst(node, -1));
+
+   TR::Node* mismatchElementIndex = TR::Node::create(node, TR::l2i, 1, TR::Node::create(node, TR::lshr, 2, mismatchByteIndex, log2ArrayIndexScale));
+   TR::Node* noMismatchFound = TR::Node::create(node, TR::lcmpeq, 2, mismatchByteIndex, lengthToCompare);
+
+   anchorAllChildren(node, treetop);
+   prepareToReplaceNode(node);
+
+   TR::Node::recreate(node, TR::iselect);
+   node->setNumChildren(3);
+   node->setAndIncChild(0, noMismatchFound);
+   node->setAndIncChild(1, invertedRemainder);
+   node->setAndIncChild(2, mismatchElementIndex);
+
+   TR::TransformUtil::removeTree(comp(), treetop);
+   }
+
 void J9::RecognizedCallTransformer::process_java_lang_StrictMath_and_Math_sqrt(TR::TreeTop* treetop, TR::Node* node)
    {
    TR::Node* valueNode = node->getLastChild();
@@ -1138,6 +1192,8 @@ bool J9::RecognizedCallTransformer::isInlineable(TR::TreeTop* treetop)
          case TR::java_lang_StringCoding_encodeASCII:
          case TR::java_lang_String_encodeASCII:
             return comp()->cg()->getSupportsInlineEncodeASCII();
+         case TR::jdk_internal_util_ArraysSupport_vectorizedMismatch:
+            return comp()->cg()->getSupportsInlineVectorizedMismatch();
          default:
             return false;
          }
@@ -1273,6 +1329,9 @@ void J9::RecognizedCallTransformer::transform(TR::TreeTop* treetop)
          case TR::java_lang_Long_reverseBytes:
             processIntrinsicFunction(treetop, node, TR::lbyteswap);
             break;
+         case TR::jdk_internal_util_ArraysSupport_vectorizedMismatch:
+            process_jdk_internal_util_ArraysSupport_vectorizedMismatch(treetop, node);
+            break;
          default:
             break;
          }

diff --git a/runtime/compiler/optimizer/J9RecognizedCallTransformer.hpp b/runtime/compiler/optimizer/J9RecognizedCallTransformer.hpp
@@ -139,6 +139,88 @@ class RecognizedCallTransformer : public OMR::RecognizedCallTransformer
     *     \endcode
     */
    void process_java_lang_StringUTF16_toBytes(TR::TreeTop* treetop, TR::Node* node);
+   /** \brief
+    *     Transforms jdk/internal/util/ArraysSupport.vectorizedMismatch(Ljava/lang/Object;JLjava/lang/Object;JII)I
+    *     into an arraycmplen, bit manipulation and iselect sequence with equivalent semantics.
+    *
+    *  \param treetop
+    *     The treetop which anchors the call node.
+    *
+    *  \param node
+    *     The call node representing a call to jdk/internal/util/ArraysSupport.vectorizedMismatch(Ljava/lang/Object;JLjava/lang/Object;JII)I
+    *     which has the following shape:
+    *
+    *     \code
+    *     icall  <jdk/internal/util/ArraysSupport.vectorizedMismatch(Ljava/lang/Object;JLjava/lang/Object;JII)I>
+    *       <a>
+    *       <aOffset>
+    *       <b>
+    *       <bOffset>
+    *       <length>
+    *       <log2ArrayIndexScale>
+    *     \endcode
+    *
+    *  \details
+    *     The call node is transformed to the following shape:
+    *
+    *     \code
+    *     iselect ()
+    *       lcmpeq
+    *         arraycmplen
+    *           aladd
+    *             <a>
+    *             <aOffset>
+    *           aladd
+    *             <b>
+    *             <bOffset>
+    *           land
+    *             lshl
+    *               i2l
+    *                 <length>
+    *               <log2ArrayIndexScale>
+    *             lxor
+    *               lor
+    *                 lshl
+    *                   ==>i2l
+    *                   iconst 1
+    *                 lconst 3
+    *               lconst -1
+    *         ==>land
+    *       ixor
+    *         l2i
+    *           lshr
+    *             land
+    *               ==>lshl
+    *               ==>lor
+    *             <log2ArrayIndexScale>
+    *         iconst -1
+    *       l2i
+    *         lshr
+    *           ==>arraycmplen
+    *           <log2ArrayIndexScale>
+    *     \endcode
+    *
+    *     This transformation is valid because vectorizedMismatch is functionally equivalent to the following pseudocode
+    *
+    *     \code
+    *     vectorizedMismatch(a, aOffset, b, bOffset, length, log2ArrayIndexScale) {
+    *         lengthInBytes = length << log2ArrayIndexScale
+    *
+    *         // the following mask calculation is equivalent to 'mask = (log2ArrayIndexScale<2) ? 3 : 7', assuming log2ArrayIndexScale <= 3
+    *         // the original java implementation checks multiple of 8B at a time, but for elements smaller than 4B it also checks another 4B at the end
+    *         // this mask serves to round down to nearest multiple of 8B (or 4B if the element is smaller than 4B) and get remainder
+    *         mask = (log2ArrayIndexScale<<1) | 3
+    *
+    *         lengthToCompare = lengthInBytes & ~(mask)                          // round down to nearest multiple of 8 (or 4)
+    *         mismatchIndex = arrayCmpLen(a+aOffset, b+bOffset, lengthToCompare)
+    *         if (mismatchIndex == lengthToCompare)                              // no mismatch found
+    *             return ~((lengthInBytes & mask) >> log2ArrayIndexScale)        // inverted remainder, converted from byte-wise index to element-wise index
+    *         else                                                               // mismatch found
+    *             return mismatchIndex >> log2ArrayIndexScale                    // convert byte-wise index to element-wise index
+    *     }
+    *     \endcode
+    */
+   void process_jdk_internal_util_ArraysSupport_vectorizedMismatch(TR::TreeTop* treetop, TR::Node* node);
    /** \brief
     *     Transforms java/lang/StrictMath.sqrt(D)D and java/lang/Math.sqrt(D)D into a CodeGen inlined function with equivalent semantics.
     *

diff --git a/runtime/compiler/p/codegen/J9CodeGenerator.cpp b/runtime/compiler/p/codegen/J9CodeGenerator.cpp
@@ -77,6 +77,12 @@ J9::Power::CodeGenerator::initialize()
       cg->setSupportsInlineConcurrentLinkedQueue();
       }
 
+   static bool disableInlineVectorizedMismatch = feGetEnv("TR_disableInlineVectorizedMismatch") != NULL;
+   if (cg->getSupportsArrayCmpLen() && !disableInlineVectorizedMismatch)
+      {
+      cg->setSupportsInlineVectorizedMismatch();
+      }
+
    cg->setSupportsNewInstanceImplOpt();
 
    static char *disableMonitorCacheLookup = feGetEnv("TR_disableMonitorCacheLookup");

diff --git a/runtime/compiler/x/codegen/J9CodeGenerator.cpp b/runtime/compiler/x/codegen/J9CodeGenerator.cpp
@@ -135,6 +135,12 @@ J9::X86::CodeGenerator::initialize()
       cg->setSupportsBDLLHardwareOverflowCheck();
       }
 
+   static bool disableInlineVectorizedMismatch = feGetEnv("TR_disableInlineVectorizedMismatch") != NULL;
+   if (cg->getSupportsArrayCmpLen() && !disableInlineVectorizedMismatch)
+      {
+      cg->setSupportsInlineVectorizedMismatch();
+      }
+
    // Disable fast gencon barriers for AOT compiles because relocations on
    // the inlined heap addresses are not available (yet).
    //

diff --git a/runtime/compiler/z/codegen/J9CodeGenerator.cpp b/runtime/compiler/z/codegen/J9CodeGenerator.cpp
@@ -124,6 +124,12 @@ J9::Z::CodeGenerator::initialize()
       cg->setSupportsInlineEncodeASCII();
       }
 
+   static bool disableInlineVectorizedMismatch = feGetEnv("TR_disableInlineVectorizedMismatch") != NULL;
+   if (cg->getSupportsArrayCmpLen() && !disableInlineVectorizedMismatch)
+      {
+      cg->setSupportsInlineVectorizedMismatch();
+      }
+
    // Let's turn this on.  There is more work needed in the opt
    // to catch the case where the BNDSCHK is inserted after
    //