Reviewers: jarin,
Description:
Fix bug in optimization of Uint32LessThan.
[email protected]
BUG=
Please review this at https://codereview.chromium.org/689883003/
Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+66, -6 lines):
M src/compiler/machine-operator-reducer.cc
A test/mjsunit/asm/uint32-less-than-shift.js
M test/unittests/compiler/machine-operator-reducer-unittest.cc
Index: src/compiler/machine-operator-reducer.cc
diff --git a/src/compiler/machine-operator-reducer.cc
b/src/compiler/machine-operator-reducer.cc
index
98873c3f1e3bfe02b61f9713160fb7b16b3db5a6..7e55a28d2137c4a7628970f68d1f40ca24c46634
100644
--- a/src/compiler/machine-operator-reducer.cc
+++ b/src/compiler/machine-operator-reducer.cc
@@ -370,13 +370,13 @@ Reduction MachineOperatorReducer::Reduce(Node* node) {
if (m.left().IsWord32Sar() && m.right().HasValue()) {
Int32BinopMatcher mleft(m.left().node());
if (mleft.right().HasValue()) {
- // (x >> K) < C => x < (C << K) | (2^K - 1)
+ // (x >> K) < C => x < (C << K)
// when C < (M >> K)
const uint32_t c = m.right().Value();
const uint32_t k = mleft.right().Value() & 0x1f;
if (c < static_cast<uint32_t>(kMaxInt >> k)) {
node->ReplaceInput(0, mleft.left().node());
- node->ReplaceInput(1, Uint32Constant((c << k) | ((1 << k) -
1)));
+ node->ReplaceInput(1, Uint32Constant(c << k));
return Changed(node);
}
}
Index: test/mjsunit/asm/uint32-less-than-shift.js
diff --git a/test/mjsunit/asm/uint32-less-than-shift.js
b/test/mjsunit/asm/uint32-less-than-shift.js
new file mode 100644
index
0000000000000000000000000000000000000000..7384e21ebd3f366d5ca6d8e78aeaba6ee196f44c
--- /dev/null
+++ b/test/mjsunit/asm/uint32-less-than-shift.js
@@ -0,0 +1,61 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function Module(stdlib, foreign, heap) {
+ 'use asm';
+
+ function foo1(i1) {
+ i1 = i1 | 0;
+ var i10 = i1 >> 5;
+ if (i10 >>> 0 < 5) {
+ return 1;
+ } else {
+ return 0;
+ }
+ return 0;
+ }
+
+ function foo2(i1) {
+ i1 = i1 | 0;
+ var i10 = i1 / 32 | 0;
+ if (i10 >>> 0 < 5) {
+ return 1;
+ } else {
+ return 0;
+ }
+ return 0;
+ }
+
+ function foo3(i1) {
+ i1 = i1 | 0;
+ var i10 = (i1 + 32 | 0) / 32 | 0;
+ if (i10 >>> 0 < 5) {
+ return 1;
+ } else {
+ return 0;
+ }
+ return 0;
+ }
+ return {foo1: foo1, foo2: foo2, foo3: foo3};
+}
+
+var m = Module(this, {}, undefined);
+
+for (var i = 0; i < 4 * 32; i++) {
+ assertEquals(1, m.foo1(i));
+ assertEquals(1, m.foo2(i));
+ assertEquals(1, m.foo3(i));
+}
+
+for (var i = 4 * 32; i < 5 * 32; i++) {
+ assertEquals(1, m.foo1(i));
+ assertEquals(1, m.foo2(i));
+ assertEquals(0, m.foo3(i));
+}
+
+for (var i = 5 * 32; i < 10 * 32; i++) {
+ assertEquals(0, m.foo1(i));
+ assertEquals(0, m.foo2(i));
+ assertEquals(0, m.foo3(i));
+}
Index: test/unittests/compiler/machine-operator-reducer-unittest.cc
diff --git a/test/unittests/compiler/machine-operator-reducer-unittest.cc
b/test/unittests/compiler/machine-operator-reducer-unittest.cc
index
fff6f96709d072ecf055c927800d2532a73280c3..be22bfdb3c841560c2d679411979dee4c2ee2ed6
100644
--- a/test/unittests/compiler/machine-operator-reducer-unittest.cc
+++ b/test/unittests/compiler/machine-operator-reducer-unittest.cc
@@ -1089,10 +1089,9 @@ TEST_F(MachineOperatorReducerTest,
Uint32LessThanWithWord32Sar) {
Reduction r = Reduce(node);
ASSERT_TRUE(r.Changed());
- EXPECT_THAT(
- r.replacement(),
- IsUint32LessThan(p0, IsInt32Constant(bit_cast<int32_t>(
- (limit << shift) | ((1u << shift) -
1)))));
+ EXPECT_THAT(r.replacement(),
+ IsUint32LessThan(
+ p0, IsInt32Constant(bit_cast<int32_t>(limit <<
shift))));
}
}
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