Revision: 11390
Author: [email protected]
Date: Thu Apr 19 06:24:15 2012
Log: Optimize ~~(expr) in optimized code.
~~ is commonly used to truncate a value to int32 (ToInt32).
This change avoid actually emitting the bitwise operations, and
just truncates the subexpression of ~~.
BUG=v8:2037
TEST=test/mjsunit/compiler/optimize-bitnot.js
Review URL: https://chromiumcodereview.appspot.com/10123007
http://code.google.com/p/v8/source/detail?r=11390
Added:
/branches/bleeding_edge/test/mjsunit/compiler/optimize-bitnot.js
Modified:
/branches/bleeding_edge/src/arm/lithium-arm.cc
/branches/bleeding_edge/src/hydrogen-instructions.cc
/branches/bleeding_edge/src/hydrogen-instructions.h
/branches/bleeding_edge/src/ia32/lithium-ia32.cc
/branches/bleeding_edge/src/mips/lithium-mips.cc
/branches/bleeding_edge/src/x64/lithium-x64.cc
=======================================
--- /dev/null
+++ /branches/bleeding_edge/test/mjsunit/compiler/optimize-bitnot.js Thu
Apr 19 06:24:15 2012
@@ -0,0 +1,42 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --allow-natives-syntax
+
+function f(x) {
+ return ~~x;
+}
+
+f(42);
+f(42);
+%OptimizeFunctionOnNextCall(f);
+assertEquals(42, f(42));
+assertEquals(42, f(42.5));
+assertEquals(1/0, 1/f(-0));
+assertEquals(-1, f(0xffffffff));
+assertEquals(0, f(undefined));
+assertEquals(0, f("abc"));
=======================================
--- /branches/bleeding_edge/src/arm/lithium-arm.cc Wed Apr 11 06:40:55 2012
+++ /branches/bleeding_edge/src/arm/lithium-arm.cc Thu Apr 19 06:24:15 2012
@@ -1295,6 +1295,7 @@
LInstruction* LChunkBuilder::DoBitNot(HBitNot* instr) {
ASSERT(instr->value()->representation().IsInteger32());
ASSERT(instr->representation().IsInteger32());
+ if (instr->HasNoUses()) return NULL;
LOperand* value = UseRegisterAtStart(instr->value());
return DefineAsRegister(new(zone()) LBitNotI(value));
}
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.cc Mon Apr 16
04:38:01 2012
+++ /branches/bleeding_edge/src/hydrogen-instructions.cc Thu Apr 19
06:24:15 2012
@@ -868,6 +868,17 @@
}
return this;
}
+
+
+HValue* HBitNot::Canonicalize() {
+ // Optimize ~~x, a common pattern used for ToInt32(x).
+ if (value()->IsBitNot()) {
+ HValue* result = HBitNot::cast(value())->value();
+ ASSERT(result->representation().IsInteger32());
+ return result;
+ }
+ return this;
+}
HValue* HAdd::Canonicalize() {
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.h Thu Apr 19 00:49:11
2012
+++ /branches/bleeding_edge/src/hydrogen-instructions.h Thu Apr 19 06:24:15
2012
@@ -1918,6 +1918,8 @@
}
virtual HType CalculateInferredType();
+ virtual HValue* Canonicalize();
+
DECLARE_CONCRETE_INSTRUCTION(BitNot)
protected:
=======================================
--- /branches/bleeding_edge/src/ia32/lithium-ia32.cc Wed Apr 11 06:40:55
2012
+++ /branches/bleeding_edge/src/ia32/lithium-ia32.cc Thu Apr 19 06:24:15
2012
@@ -1330,6 +1330,7 @@
LInstruction* LChunkBuilder::DoBitNot(HBitNot* instr) {
ASSERT(instr->value()->representation().IsInteger32());
ASSERT(instr->representation().IsInteger32());
+ if (instr->HasNoUses()) return NULL;
LOperand* input = UseRegisterAtStart(instr->value());
LBitNotI* result = new(zone()) LBitNotI(input);
return DefineSameAsFirst(result);
=======================================
--- /branches/bleeding_edge/src/mips/lithium-mips.cc Wed Apr 11 06:40:55
2012
+++ /branches/bleeding_edge/src/mips/lithium-mips.cc Thu Apr 19 06:24:15
2012
@@ -1296,6 +1296,7 @@
LInstruction* LChunkBuilder::DoBitNot(HBitNot* instr) {
ASSERT(instr->value()->representation().IsInteger32());
ASSERT(instr->representation().IsInteger32());
+ if (instr->HasNoUses()) return NULL;
LOperand* value = UseRegisterAtStart(instr->value());
return DefineAsRegister(new(zone()) LBitNotI(value));
}
=======================================
--- /branches/bleeding_edge/src/x64/lithium-x64.cc Wed Apr 11 06:40:55 2012
+++ /branches/bleeding_edge/src/x64/lithium-x64.cc Thu Apr 19 06:24:15 2012
@@ -1285,6 +1285,7 @@
LInstruction* LChunkBuilder::DoBitNot(HBitNot* instr) {
ASSERT(instr->value()->representation().IsInteger32());
ASSERT(instr->representation().IsInteger32());
+ if (instr->HasNoUses()) return NULL;
LOperand* input = UseRegisterAtStart(instr->value());
LBitNotI* result = new(zone()) LBitNotI(input);
return DefineSameAsFirst(result);
--
v8-dev mailing list
[email protected]
http://groups.google.com/group/v8-dev
