1 /* 2 * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 import jdk.incubator.code.*; 25 import jdk.incubator.code.dialect.java.JavaOp; 26 27 import java.util.HashMap; 28 import java.util.function.BiConsumer; 29 30 import static jdk.incubator.code.dialect.java.JavaOp.sub; 31 import static jdk.incubator.code.analysis.Patterns.*; 32 33 public final class ExpressionElimination { 34 private ExpressionElimination() { 35 } 36 37 static OpPattern negP(Pattern operand) { 38 return opP(JavaOp.NegOp.class, operand); 39 } 40 41 static OpPattern addP(Pattern lhs, Pattern rhs) { 42 return opP(JavaOp.AddOp.class, lhs, rhs); 43 } 44 45 static OpPattern mulP(Pattern lhs, Pattern rhs) { 46 return opP(JavaOp.MulOp.class, lhs, rhs); 47 } 48 49 public static <T extends Op> T eliminate(T f) { 50 // Note expression elimination and other forms of analysis is simplified if first of all expressions 51 // are normalized e.g. when they have an operand that is a constant expression 52 // and the operation is associative such as add(0, x) -> add(x, 0) 53 54 var actions = multiMatch(new HashMap<Op.Result, BiConsumer<Block.Builder, Op>>(), f) 55 .pattern(mulP(_P(), valueP(constantP(0.0d)))) 56 .pattern(mulP(valueP(constantP(0.0d)), _P())) 57 .pattern(addP(valueP(), constantP(0.0d))) 58 .pattern(addP(constantP(0.0d), valueP())) 59 .pattern(mulP(constantP(1.0d), valueP())) 60 .pattern(mulP(valueP(), constantP(1.0d))) 61 .target((ms, as) -> { 62 Value a = ms.matchedOperands().get(0); 63 as.put(ms.op().result(), (block, op) -> { 64 CopyContext cc = block.context(); 65 cc.mapValue(ms.op().result(), cc.getValue(a)); 66 }); 67 return as; 68 }) 69 // add(neg(x), y) -> sub(y, x) 70 .pattern(addP(negP(valueP()), valueP())) 71 .target((ms, as) -> { 72 Value x = ms.matchedOperands().get(0); 73 Value y = ms.matchedOperands().get(1); 74 75 as.put(ms.op().result(), (block, op) -> { 76 CopyContext cc = block.context(); 77 Op.Result r = block.op(sub(cc.getValue(y), cc.getValue(x))); 78 cc.mapValue(ms.op().result(), r); 79 }); 80 return as; 81 }) 82 .matchThenApply(); 83 84 // Eliminate 85 Op ef = f.transform(CopyContext.create(), (block, op) -> { 86 BiConsumer<Block.Builder, Op> a = actions.get(op.result()); 87 if (a != null) { 88 a.accept(block, op); 89 } else { 90 block.op(op); 91 } 92 return block; 93 }); 94 95 // Remove dead ops 96 ef = ef.transform(CopyContext.create(), (block, op) -> { 97 if (!(op instanceof Op.Pure) || 98 !op.result().uses().isEmpty()) { 99 block.op(op); 100 } 101 return block; 102 }); 103 104 @SuppressWarnings("unchecked") 105 T t = (T) ef; 106 return t; 107 } 108 }