1 /*
2 * Copyright (c) 2011, 2017, 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
25 package org.graalvm.compiler.nodes.calc;
26
27 import static org.graalvm.compiler.core.common.calc.CanonicalCondition.LT;
28
29 import org.graalvm.compiler.core.common.NumUtil;
30 import org.graalvm.compiler.core.common.calc.CanonicalCondition;
31 import org.graalvm.compiler.core.common.type.FloatStamp;
32 import org.graalvm.compiler.core.common.type.IntegerStamp;
33 import org.graalvm.compiler.core.common.type.StampFactory;
34 import org.graalvm.compiler.debug.GraalError;
35 import org.graalvm.compiler.graph.Node;
36 import org.graalvm.compiler.graph.NodeClass;
37 import org.graalvm.compiler.graph.spi.CanonicalizerTool;
38 import org.graalvm.compiler.nodeinfo.NodeInfo;
39 import org.graalvm.compiler.nodes.ConstantNode;
40 import org.graalvm.compiler.nodes.LogicConstantNode;
41 import org.graalvm.compiler.nodes.LogicNegationNode;
42 import org.graalvm.compiler.nodes.LogicNode;
43 import org.graalvm.compiler.nodes.NodeView;
44 import org.graalvm.compiler.nodes.ValueNode;
45 import org.graalvm.compiler.options.OptionValues;
46
47 import jdk.vm.ci.code.CodeUtil;
48 import jdk.vm.ci.meta.Constant;
49 import jdk.vm.ci.meta.ConstantReflectionProvider;
50 import jdk.vm.ci.meta.JavaConstant;
51 import jdk.vm.ci.meta.JavaKind;
52 import jdk.vm.ci.meta.MetaAccessProvider;
53 import jdk.vm.ci.meta.PrimitiveConstant;
54
55 @NodeInfo(shortName = "<")
56 public final class IntegerLessThanNode extends IntegerLowerThanNode {
57 public static final NodeClass<IntegerLessThanNode> TYPE = NodeClass.create(IntegerLessThanNode.class);
58 private static final LessThanOp OP = new LessThanOp();
59
60 public IntegerLessThanNode(ValueNode x, ValueNode y) {
61 super(TYPE, x, y, OP);
62 assert !x.getStackKind().isNumericFloat() && x.getStackKind() != JavaKind.Object;
63 assert !y.getStackKind().isNumericFloat() && y.getStackKind() != JavaKind.Object;
64 }
65
66 public static LogicNode create(ValueNode x, ValueNode y, NodeView view) {
67 return OP.create(x, y, view);
68 }
69
70 public static LogicNode create(ConstantReflectionProvider constantReflection, MetaAccessProvider metaAccess, OptionValues options, Integer smallestCompareWidth,
71 ValueNode x, ValueNode y, NodeView view) {
72 LogicNode value = OP.canonical(constantReflection, metaAccess, options, smallestCompareWidth, OP.getCondition(), false, x, y, view);
73 if (value != null) {
74 return value;
75 }
76 return create(x, y, view);
77 }
78
79 @Override
80 public Node canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {
81 NodeView view = NodeView.from(tool);
82 ValueNode value = OP.canonical(tool.getConstantReflection(), tool.getMetaAccess(), tool.getOptions(), tool.smallestCompareWidth(), OP.getCondition(), false, forX, forY, view);
83 if (value != null) {
84 return value;
85 }
86 return this;
87 }
88
89 public static boolean subtractMayUnderflow(long x, long y, long minValue) {
90 long r = x - y;
91 // HD 2-12 Overflow iff the arguments have different signs and
92 // the sign of the result is different than the sign of x
93 return (((x ^ y) & (x ^ r)) < 0) || r <= minValue;
94 }
95
96 public static boolean subtractMayOverflow(long x, long y, long maxValue) {
97 long r = x - y;
98 // HD 2-12 Overflow iff the arguments have different signs and
99 // the sign of the result is different than the sign of x
100 return (((x ^ y) & (x ^ r)) < 0) || r > maxValue;
101 }
102
103 public static class LessThanOp extends LowerOp {
104 @Override
105 protected CompareNode duplicateModified(ValueNode newX, ValueNode newY, boolean unorderedIsTrue, NodeView view) {
106 if (newX.stamp(view) instanceof FloatStamp && newY.stamp(view) instanceof FloatStamp) {
107 return new FloatLessThanNode(newX, newY, unorderedIsTrue); // TODO: Is the last arg
108 // supposed to be true?
109 } else if (newX.stamp(view) instanceof IntegerStamp && newY.stamp(view) instanceof IntegerStamp) {
110 return new IntegerLessThanNode(newX, newY);
111 }
112 throw GraalError.shouldNotReachHere();
113 }
114
115 @Override
116 protected LogicNode optimizeNormalizeCompare(ConstantReflectionProvider constantReflection, MetaAccessProvider metaAccess, OptionValues options, Integer smallestCompareWidth,
117 Constant constant, NormalizeCompareNode normalizeNode, boolean mirrored, NodeView view) {
118 PrimitiveConstant primitive = (PrimitiveConstant) constant;
119 /* @formatter:off
120 * a NC b < c (not mirrored)
121 * cases for c:
122 * 0 -> a < b
123 * [MIN, -1] -> false
124 * 1 -> a <= b
125 * [2, MAX] -> true
126 * unordered-is-less means unordered-is-true.
127 *
128 * c < a NC b (mirrored)
129 * cases for c:
130 * 0 -> a > b
131 * [1, MAX] -> false
132 * -1 -> a >= b
133 * [MIN, -2] -> true
134 * unordered-is-less means unordered-is-false.
135 *
136 * We can handle mirroring by swapping a & b and negating the constant.
137 * @formatter:on
138 */
139 ValueNode a = mirrored ? normalizeNode.getY() : normalizeNode.getX();
140 ValueNode b = mirrored ? normalizeNode.getX() : normalizeNode.getY();
141 long cst = mirrored ? -primitive.asLong() : primitive.asLong();
142
143 if (cst == 0) {
144 if (normalizeNode.getX().getStackKind() == JavaKind.Double || normalizeNode.getX().getStackKind() == JavaKind.Float) {
145 return FloatLessThanNode.create(constantReflection, metaAccess, options, smallestCompareWidth, a, b, mirrored ^ normalizeNode.isUnorderedLess, view);
146 } else {
147 return IntegerLessThanNode.create(constantReflection, metaAccess, options, smallestCompareWidth, a, b, view);
148 }
149 } else if (cst == 1) {
150 // a <= b <=> !(a > b)
151 LogicNode compare;
152 if (normalizeNode.getX().getStackKind() == JavaKind.Double || normalizeNode.getX().getStackKind() == JavaKind.Float) {
153 // since we negate, we have to reverse the unordered result
154 compare = FloatLessThanNode.create(constantReflection, metaAccess, options, smallestCompareWidth, b, a, mirrored == normalizeNode.isUnorderedLess, view);
155 } else {
156 compare = IntegerLessThanNode.create(constantReflection, metaAccess, options, smallestCompareWidth, b, a, view);
157 }
158 return LogicNegationNode.create(compare);
159 } else if (cst <= -1) {
160 return LogicConstantNode.contradiction();
161 } else {
162 assert cst >= 2;
163 return LogicConstantNode.tautology();
164 }
165 }
166
167 @Override
168 protected LogicNode findSynonym(ValueNode forX, ValueNode forY, NodeView view) {
169 LogicNode result = super.findSynonym(forX, forY, view);
170 if (result != null) {
171 return result;
172 }
173 if (forX.stamp(view) instanceof IntegerStamp && forY.stamp(view) instanceof IntegerStamp) {
174 if (IntegerStamp.sameSign((IntegerStamp) forX.stamp(view), (IntegerStamp) forY.stamp(view))) {
175 return new IntegerBelowNode(forX, forY);
176 }
177 }
178 if (forY.isConstant() && forX instanceof SubNode) {
179 SubNode sub = (SubNode) forX;
180 ValueNode xx = null;
181 ValueNode yy = null;
182 boolean negate = false;
183 if (forY.asConstant().isDefaultForKind()) {
184 // (x - y) < 0 when x - y is known not to underflow <=> x < y
185 xx = sub.getX();
186 yy = sub.getY();
187 } else if (forY.isJavaConstant() && forY.asJavaConstant().asLong() == 1) {
188 // (x - y) < 1 when x - y is known not to underflow <=> !(y < x)
189 xx = sub.getY();
190 yy = sub.getX();
191 negate = true;
192 }
193 if (xx != null) {
194 assert yy != null;
195 IntegerStamp xStamp = (IntegerStamp) sub.getX().stamp(view);
196 IntegerStamp yStamp = (IntegerStamp) sub.getY().stamp(view);
197 long minValue = CodeUtil.minValue(xStamp.getBits());
198 long maxValue = CodeUtil.maxValue(xStamp.getBits());
199
200 if (!subtractMayUnderflow(xStamp.lowerBound(), yStamp.upperBound(), minValue) && !subtractMayOverflow(xStamp.upperBound(), yStamp.lowerBound(), maxValue)) {
201 LogicNode logic = new IntegerLessThanNode(xx, yy);
202 if (negate) {
203 logic = LogicNegationNode.create(logic);
204 }
205 return logic;
206 }
207 }
208 }
209
210 if (forX.stamp(view) instanceof IntegerStamp) {
211 assert forY.stamp(view) instanceof IntegerStamp;
212 int bits = ((IntegerStamp) forX.stamp(view)).getBits();
213 assert ((IntegerStamp) forY.stamp(view)).getBits() == bits;
214 long min = OP.minValue(bits);
215 long xResidue = 0;
216 ValueNode left = null;
217 JavaConstant leftCst = null;
218 if (forX instanceof AddNode) {
219 AddNode xAdd = (AddNode) forX;
220 if (xAdd.getY().isJavaConstant()) {
221 long xCst = xAdd.getY().asJavaConstant().asLong();
222 xResidue = xCst - min;
223 left = xAdd.getX();
224 }
225 } else if (forX.isJavaConstant()) {
226 leftCst = forX.asJavaConstant();
227 }
228 if (left != null || leftCst != null) {
229 long yResidue = 0;
230 ValueNode right = null;
231 JavaConstant rightCst = null;
232 if (forY instanceof AddNode) {
233 AddNode yAdd = (AddNode) forY;
234 if (yAdd.getY().isJavaConstant()) {
235 long yCst = yAdd.getY().asJavaConstant().asLong();
236 yResidue = yCst - min;
237 right = yAdd.getX();
238 }
239 } else if (forY.isJavaConstant()) {
240 rightCst = forY.asJavaConstant();
241 }
242 if (right != null || rightCst != null) {
243 if ((xResidue == 0 && left != null) || (yResidue == 0 && right != null)) {
244 if (left == null) {
245 left = ConstantNode.forIntegerBits(bits, leftCst.asLong() - min);
246 } else if (xResidue != 0) {
247 left = AddNode.create(left, ConstantNode.forIntegerBits(bits, xResidue), view);
248 }
249 if (right == null) {
250 right = ConstantNode.forIntegerBits(bits, rightCst.asLong() - min);
251 } else if (yResidue != 0) {
252 right = AddNode.create(right, ConstantNode.forIntegerBits(bits, yResidue), view);
253 }
254 return new IntegerBelowNode(left, right);
255 }
256 }
257 }
258 }
259 return null;
260 }
261
262 @Override
263 protected CanonicalCondition getCondition() {
264 return LT;
265 }
266
267 @Override
268 protected IntegerLowerThanNode createNode(ValueNode x, ValueNode y) {
269 return new IntegerLessThanNode(x, y);
270 }
271
272 @Override
273 protected long upperBound(IntegerStamp stamp) {
274 return stamp.upperBound();
275 }
276
277 @Override
278 protected long lowerBound(IntegerStamp stamp) {
279 return stamp.lowerBound();
280 }
281
282 @Override
283 protected int compare(long a, long b) {
284 return Long.compare(a, b);
285 }
286
287 @Override
288 protected long min(long a, long b) {
289 return Math.min(a, b);
290 }
291
292 @Override
293 protected long max(long a, long b) {
294 return Math.max(a, b);
295 }
296
297 @Override
298 protected long cast(long a, int bits) {
299 return CodeUtil.signExtend(a, bits);
300 }
301
302 @Override
303 protected long minValue(int bits) {
304 return NumUtil.minValue(bits);
305 }
306
307 @Override
308 protected long maxValue(int bits) {
309 return NumUtil.maxValue(bits);
310 }
311
312 @Override
313 protected IntegerStamp forInteger(int bits, long min, long max) {
314 return StampFactory.forInteger(bits, cast(min, bits), cast(max, bits));
315 }
316 }
317 }