Revision: 15546
Author: [email protected]
Date: Mon Jul 8 04:15:24 2013
Log: Fix and cleanup can_be_minus_zero computation
[email protected]
Review URL: https://codereview.chromium.org/18434004
http://code.google.com/p/v8/source/detail?r=15546
Added:
/branches/bleeding_edge/test/mjsunit/compiler/minus-zero.js
Modified:
/branches/bleeding_edge/src/hydrogen-instructions.cc
=======================================
--- /dev/null
+++ /branches/bleeding_edge/test/mjsunit/compiler/minus-zero.js Mon Jul 8
04:15:24 2013
@@ -0,0 +1,37 @@
+// Copyright 2013 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 add(x, y) {
+ return x + y;
+}
+
+assertEquals(0, add(0, 0));
+assertEquals(0, add(0, 0));
+%OptimizeFunctionOnNextCall(add);
+assertEquals(-0, add(-0, -0));
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.cc Mon Jul 8
02:00:59 2013
+++ /branches/bleeding_edge/src/hydrogen-instructions.cc Mon Jul 8
04:15:24 2013
@@ -1745,9 +1745,10 @@
result = new(zone) Range(Smi::kMinValue, Smi::kMaxValue);
result->set_can_be_minus_zero(false);
} else {
- // Untagged integer32 cannot be -0, all other representations can.
result = new(zone) Range();
- result->set_can_be_minus_zero(!representation().IsInteger32());
+ result->set_can_be_minus_zero(!CheckFlag(kAllUsesTruncatingToInt32));
+ // TODO(jkummerow): The range cannot be minus zero when the upper type
+ // bound is Integer32.
}
return result;
}
@@ -1765,7 +1766,8 @@
Range* result = (input_range != NULL)
? input_range->Copy(zone)
: HValue::InferRange(zone);
- if (to().IsInteger32()) result->set_can_be_minus_zero(false);
+ result->set_can_be_minus_zero(!to().IsSmiOrInteger32() ||
+ !CheckFlag(kAllUsesTruncatingToInt32));
return result;
}
@@ -1810,9 +1812,8 @@
CheckFlag(kAllUsesTruncatingToInt32)) {
ClearFlag(kCanOverflow);
}
- if (!CheckFlag(kAllUsesTruncatingToInt32)) {
- res->set_can_be_minus_zero(a->CanBeMinusZero() &&
b->CanBeMinusZero());
- }
+ res->set_can_be_minus_zero(!CheckFlag(kAllUsesTruncatingToInt32) &&
+ a->CanBeMinusZero() && b->CanBeMinusZero());
return res;
} else {
return HValue::InferRange(zone);
@@ -1829,9 +1830,8 @@
CheckFlag(kAllUsesTruncatingToInt32)) {
ClearFlag(kCanOverflow);
}
- if (!CheckFlag(kAllUsesTruncatingToInt32)) {
- res->set_can_be_minus_zero(a->CanBeMinusZero() && b->CanBeZero());
- }
+ res->set_can_be_minus_zero(!CheckFlag(kAllUsesTruncatingToInt32) &&
+ a->CanBeMinusZero() && b->CanBeZero());
return res;
} else {
return HValue::InferRange(zone);
@@ -1850,11 +1850,9 @@
// precise and therefore not the same as converting to Double and
back.
ClearFlag(kCanOverflow);
}
- if (!CheckFlag(kAllUsesTruncatingToInt32)) {
- bool m0 = (a->CanBeZero() && b->CanBeNegative()) ||
- (a->CanBeNegative() && b->CanBeZero());
- res->set_can_be_minus_zero(m0);
- }
+ res->set_can_be_minus_zero(!CheckFlag(kAllUsesTruncatingToInt32) &&
+ ((a->CanBeZero() && b->CanBeNegative()) ||
+ (a->CanBeNegative() && b->CanBeZero())));
return res;
} else {
return HValue::InferRange(zone);
@@ -1867,16 +1865,9 @@
Range* a = left()->range();
Range* b = right()->range();
Range* result = new(zone) Range();
- if (!CheckFlag(kAllUsesTruncatingToInt32)) {
- if (a->CanBeMinusZero()) {
- result->set_can_be_minus_zero(true);
- }
-
- if (a->CanBeZero() && b->CanBeNegative()) {
- result->set_can_be_minus_zero(true);
- }
- }
-
+ result->set_can_be_minus_zero(!CheckFlag(kAllUsesTruncatingToInt32) &&
+ (a->CanBeMinusZero() ||
+ (a->CanBeZero() &&
b->CanBeNegative())));
if (!a->Includes(kMinInt) || !b->Includes(-1)) {
ClearFlag(HValue::kCanOverflow);
}
@@ -1906,9 +1897,8 @@
Range* result = new(zone) Range(left_can_be_negative ?
-positive_bound : 0,
a->CanBePositive() ? positive_bound :
0);
- if (left_can_be_negative && !CheckFlag(kAllUsesTruncatingToInt32)) {
- result->set_can_be_minus_zero(true);
- }
+ result->set_can_be_minus_zero(!CheckFlag(kAllUsesTruncatingToInt32) &&
+ left_can_be_negative);
if (!a->Includes(kMinInt) || !b->Includes(-1)) {
ClearFlag(HValue::kCanOverflow);
@@ -2458,7 +2448,9 @@
? static_cast<int32_t>(-limit) : 0;
return new(zone) Range(min, static_cast<int32_t>(limit - 1));
}
- return HValue::InferRange(zone);
+ Range* result = HValue::InferRange(zone);
+ result->set_can_be_minus_zero(false);
+ return result;
}
const int32_t kDefaultMask = static_cast<int32_t>(0xffffffff);
int32_t left_mask = (left()->range() != NULL)
@@ -2470,9 +2462,11 @@
int32_t result_mask = (op() == Token::BIT_AND)
? left_mask & right_mask
: left_mask | right_mask;
- return (result_mask >= 0)
- ? new(zone) Range(0, result_mask)
- : HValue::InferRange(zone);
+ if (result_mask >= 0) return new(zone) Range(0, result_mask);
+
+ Range* result = HValue::InferRange(zone);
+ result->set_can_be_minus_zero(false);
+ return result;
}
@@ -2484,7 +2478,6 @@
? left()->range()->Copy(zone)
: new(zone) Range();
result->Sar(c->Integer32Value());
- result->set_can_be_minus_zero(false);
return result;
}
}
@@ -2509,7 +2502,6 @@
? left()->range()->Copy(zone)
: new(zone) Range();
result->Sar(c->Integer32Value());
- result->set_can_be_minus_zero(false);
return result;
}
}
@@ -2526,7 +2518,6 @@
? left()->range()->Copy(zone)
: new(zone) Range();
result->Shl(c->Integer32Value());
- result->set_can_be_minus_zero(false);
return result;
}
}
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