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 package org.graalvm.compiler.nodes.calc;
24
25 import static org.graalvm.compiler.core.common.calc.Condition.LT;
26
27 import jdk.vm.ci.meta.ConstantReflectionProvider;
28 import jdk.vm.ci.meta.MetaAccessProvider;
29 import org.graalvm.compiler.core.common.NumUtil;
30 import org.graalvm.compiler.core.common.calc.Condition;
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.ValueNode;
44
45 import jdk.vm.ci.code.CodeUtil;
46 import jdk.vm.ci.meta.Constant;
47 import jdk.vm.ci.meta.JavaConstant;
48 import jdk.vm.ci.meta.JavaKind;
49 import jdk.vm.ci.meta.PrimitiveConstant;
50 import org.graalvm.compiler.options.OptionValues;
51
52 @NodeInfo(shortName = "<")
53 public final class IntegerLessThanNode extends IntegerLowerThanNode {
54 public static final NodeClass<IntegerLessThanNode> TYPE = NodeClass.create(IntegerLessThanNode.class);
55 public static final LessThanOp OP = new LessThanOp();
56
57 public IntegerLessThanNode(ValueNode x, ValueNode y) {
58 super(TYPE, x, y, OP);
59 assert !x.getStackKind().isNumericFloat() && x.getStackKind() != JavaKind.Object;
60 assert !y.getStackKind().isNumericFloat() && y.getStackKind() != JavaKind.Object;
61 }
62
63 public static LogicNode create(ValueNode x, ValueNode y) {
64 return OP.create(x, y);
65 }
66
67 public static LogicNode create(ConstantReflectionProvider constantReflection, MetaAccessProvider metaAccess, OptionValues options, Integer smallestCompareWidth,
68 ValueNode x, ValueNode y) {
69 LogicNode value = OP.canonical(constantReflection, metaAccess, options, smallestCompareWidth, OP.getCondition(), false, x, y);
70 if (value != null) {
71 return value;
72 }
73 return create(x, y);
74 }
75
76 @Override
77 public Node canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {
78 ValueNode value = OP.canonical(tool.getConstantReflection(), tool.getMetaAccess(), tool.getOptions(), tool.smallestCompareWidth(), OP.getCondition(), false, forX, forY);
79 if (value != null) {
80 return value;
81 }
82 return this;
83 }
84
85 public static boolean subtractMayUnderflow(long x, long y, long minValue) {
86 long r = x - y;
87 // HD 2-12 Overflow iff the arguments have different signs and
88 // the sign of the result is different than the sign of x
89 return (((x ^ y) & (x ^ r)) < 0) || r <= minValue;
90 }
91
92 public static boolean subtractMayOverflow(long x, long y, long maxValue) {
93 long r = x - y;
94 // HD 2-12 Overflow iff the arguments have different signs and
95 // the sign of the result is different than the sign of x
96 return (((x ^ y) & (x ^ r)) < 0) || r > maxValue;
97 }
98
99 public static class LessThanOp extends LowerOp {
100 @Override
101 protected CompareNode duplicateModified(ValueNode newX, ValueNode newY, boolean unorderedIsTrue) {
102 if (newX.stamp() instanceof FloatStamp && newY.stamp() instanceof FloatStamp) {
103 return new FloatLessThanNode(newX, newY, unorderedIsTrue); // TODO: Is the last arg
104 // supposed to be true?
105 } else if (newX.stamp() instanceof IntegerStamp && newY.stamp() instanceof IntegerStamp) {
106 return new IntegerLessThanNode(newX, newY);
107 }
108 throw GraalError.shouldNotReachHere();
109 }
110
111 @Override
112 protected LogicNode optimizeNormalizeCompare(ConstantReflectionProvider constantReflection, MetaAccessProvider metaAccess, OptionValues options, Integer smallestCompareWidth,
113 Constant constant, NormalizeCompareNode normalizeNode, boolean mirrored) {
114 PrimitiveConstant primitive = (PrimitiveConstant) constant;
115 /* @formatter:off
116 * a NC b < c (not mirrored)
117 * cases for c:
118 * 0 -> a < b
119 * [MIN, -1] -> false
120 * 1 -> a <= b
121 * [2, MAX] -> true
122 * unordered-is-less means unordered-is-true.
123 *
124 * c < a NC b (mirrored)
125 * cases for c:
126 * 0 -> a > b
127 * [1, MAX] -> false
128 * -1 -> a >= b
129 * [MIN, -2] -> true
130 * unordered-is-less means unordered-is-false.
131 *
132 * We can handle mirroring by swapping a & b and negating the constant.
133 * @formatter:on
134 */
135 ValueNode a = mirrored ? normalizeNode.getY() : normalizeNode.getX();
136 ValueNode b = mirrored ? normalizeNode.getX() : normalizeNode.getY();
137 long cst = mirrored ? -primitive.asLong() : primitive.asLong();
138
139 if (cst == 0) {
140 if (normalizeNode.getX().getStackKind() == JavaKind.Double || normalizeNode.getX().getStackKind() == JavaKind.Float) {
141 return FloatLessThanNode.create(constantReflection, metaAccess, options, smallestCompareWidth, a, b, mirrored ^ normalizeNode.isUnorderedLess);
142 } else {
143 return IntegerLessThanNode.create(constantReflection, metaAccess, options, smallestCompareWidth, a, b);
144 }
145 } else if (cst == 1) {
146 // a <= b <=> !(a > b)
147 LogicNode compare;
148 if (normalizeNode.getX().getStackKind() == JavaKind.Double || normalizeNode.getX().getStackKind() == JavaKind.Float) {
149 // since we negate, we have to reverse the unordered result
150 compare = FloatLessThanNode.create(constantReflection, metaAccess, options, smallestCompareWidth, b, a, mirrored == normalizeNode.isUnorderedLess);
151 } else {
152 compare = IntegerLessThanNode.create(constantReflection, metaAccess, options, smallestCompareWidth, b, a);
153 }
154 return LogicNegationNode.create(compare);
155 } else if (cst <= -1) {
156 return LogicConstantNode.contradiction();
157 } else {
158 assert cst >= 2;
159 return LogicConstantNode.tautology();
160 }
161 }
162
163 @Override
164 protected LogicNode findSynonym(ValueNode forX, ValueNode forY) {
165 LogicNode result = super.findSynonym(forX, forY);
166 if (result != null) {
167 return result;
168 }
169 if (forX.stamp() instanceof IntegerStamp && forY.stamp() instanceof IntegerStamp) {
170 if (IntegerStamp.sameSign((IntegerStamp) forX.stamp(), (IntegerStamp) forY.stamp())) {
171 return new IntegerBelowNode(forX, forY);
172 }
173 }
174 if (forY.isConstant() && forX instanceof SubNode) {
175 SubNode sub = (SubNode) forX;
176 ValueNode xx = null;
177 ValueNode yy = null;
178 boolean negate = false;
179 if (forY.asConstant().isDefaultForKind()) {
180 // (x - y) < 0 when x - y is known not to underflow <=> x < y
181 xx = sub.getX();
182 yy = sub.getY();
183 } else if (forY.isJavaConstant() && forY.asJavaConstant().asLong() == 1) {
184 // (x - y) < 1 when x - y is known not to underflow <=> !(y < x)
185 xx = sub.getY();
186 yy = sub.getX();
187 negate = true;
188 }
189 if (xx != null) {
190 assert yy != null;
191 IntegerStamp xStamp = (IntegerStamp) sub.getX().stamp();
192 IntegerStamp yStamp = (IntegerStamp) sub.getY().stamp();
193 long minValue = CodeUtil.minValue(xStamp.getBits());
194 long maxValue = CodeUtil.maxValue(xStamp.getBits());
195
196 if (!subtractMayUnderflow(xStamp.lowerBound(), yStamp.upperBound(), minValue) && !subtractMayOverflow(xStamp.upperBound(), yStamp.lowerBound(), maxValue)) {
197 LogicNode logic = new IntegerLessThanNode(xx, yy);
198 if (negate) {
199 logic = LogicNegationNode.create(logic);
200 }
201 return logic;
202 }
203 }
204 }
205
206 int bits = ((IntegerStamp) forX.stamp()).getBits();
207 assert ((IntegerStamp) forY.stamp()).getBits() == bits;
208 long min = OP.minValue(bits);
209 long xResidue = 0;
210 ValueNode left = null;
211 JavaConstant leftCst = null;
212 if (forX instanceof AddNode) {
213 AddNode xAdd = (AddNode) forX;
214 if (xAdd.getY().isJavaConstant()) {
215 long xCst = xAdd.getY().asJavaConstant().asLong();
216 xResidue = xCst - min;
217 left = xAdd.getX();
218 }
219 } else if (forX.isJavaConstant()) {
220 leftCst = forX.asJavaConstant();
221 }
222 if (left != null || leftCst != null) {
223 long yResidue = 0;
224 ValueNode right = null;
225 JavaConstant rightCst = null;
226 if (forY instanceof AddNode) {
227 AddNode yAdd = (AddNode) forY;
228 if (yAdd.getY().isJavaConstant()) {
229 long yCst = yAdd.getY().asJavaConstant().asLong();
230 yResidue = yCst - min;
231 right = yAdd.getX();
232 }
233 } else if (forY.isJavaConstant()) {
234 rightCst = forY.asJavaConstant();
235 }
236 if (right != null || rightCst != null) {
237 if ((xResidue == 0 && left != null) || (yResidue == 0 && right != null)) {
238 if (left == null) {
239 left = ConstantNode.forIntegerBits(bits, leftCst.asLong() - min);
240 } else if (xResidue != 0) {
241 left = AddNode.create(left, ConstantNode.forIntegerBits(bits, xResidue));
242 }
243 if (right == null) {
244 right = ConstantNode.forIntegerBits(bits, rightCst.asLong() - min);
245 } else if (yResidue != 0) {
246 right = AddNode.create(right, ConstantNode.forIntegerBits(bits, yResidue));
247 }
248 return new IntegerBelowNode(left, right);
249 }
250 }
251 }
252 return null;
253 }
254
255 @Override
256 protected Condition getCondition() {
257 return LT;
258 }
259
260 @Override
261 protected IntegerLowerThanNode createNode(ValueNode x, ValueNode y) {
262 return new IntegerLessThanNode(x, y);
263 }
264
265 @Override
266 protected long upperBound(IntegerStamp stamp) {
267 return stamp.upperBound();
268 }
269
270 @Override
271 protected long lowerBound(IntegerStamp stamp) {
272 return stamp.lowerBound();
273 }
274
275 @Override
276 protected int compare(long a, long b) {
277 return Long.compare(a, b);
278 }
279
280 @Override
281 protected long min(long a, long b) {
282 return Math.min(a, b);
283 }
284
285 @Override
286 protected long max(long a, long b) {
287 return Math.max(a, b);
288 }
289
290 @Override
291 protected long cast(long a, int bits) {
292 return CodeUtil.signExtend(a, bits);
293 }
294
295 @Override
296 protected long minValue(int bits) {
297 return NumUtil.minValue(bits);
298 }
299
300 @Override
301 protected long maxValue(int bits) {
302 return NumUtil.maxValue(bits);
303 }
304
305 @Override
306 protected IntegerStamp forInteger(int bits, long min, long max) {
307 return StampFactory.forInteger(bits, cast(min, bits), cast(max, bits));
308 }
309 }
310 }