Revision: 12216
Author: [email protected]
Date: Mon Jul 30 01:34:26 2012
Log: Make sure double to int conversion is correct.
[email protected]
BUG=v8:2260
TEST=test-utils/Utils1
Review URL: https://chromiumcodereview.appspot.com/10820047
http://code.google.com/p/v8/source/detail?r=12216
Modified:
/branches/bleeding_edge/src/conversions.h
/branches/bleeding_edge/src/elements.cc
/branches/bleeding_edge/src/runtime.cc
/branches/bleeding_edge/test/cctest/test-utils.cc
=======================================
--- /branches/bleeding_edge/src/conversions.h Tue Nov 29 02:56:11 2011
+++ /branches/bleeding_edge/src/conversions.h Mon Jul 30 01:34:26 2012
@@ -55,6 +55,16 @@
inline double SignedZero(bool negative) {
return negative ? -0.0 : 0.0;
}
+
+
+// The fast double-to-(unsigned-)int conversion routine does not guarantee
+// rounding towards zero.
+// For NaN and values outside the int range, return INT_MIN or INT_MAX.
+inline int FastD2IChecked(double x) {
+ if (!(x >= INT_MIN)) return INT_MIN; // Negation to catch NaNs.
+ if (x > INT_MAX) return INT_MAX;
+ return static_cast<int>(x);
+}
// The fast double-to-(unsigned-)int conversion routine does not guarantee
@@ -62,8 +72,6 @@
// The result is unspecified if x is infinite or NaN, or if the rounded
// integer value is outside the range of type int.
inline int FastD2I(double x) {
- // The static_cast convertion from double to int used to be slow, but
- // as new benchmarks show, now it is much faster than lrint().
return static_cast<int>(x);
}
=======================================
--- /branches/bleeding_edge/src/elements.cc Tue Jun 12 08:30:16 2012
+++ /branches/bleeding_edge/src/elements.cc Mon Jul 30 01:34:26 2012
@@ -800,7 +800,7 @@
}
} else {
// Otherwise, fill the unused tail with holes.
- int old_length = FastD2I(array->length()->Number());
+ int old_length = FastD2IChecked(array->length()->Number());
for (int i = length; i < old_length; i++) {
backing_store->set_the_hole(i);
}
=======================================
--- /branches/bleeding_edge/src/runtime.cc Mon Jul 23 07:55:12 2012
+++ /branches/bleeding_edge/src/runtime.cc Mon Jul 30 01:34:26 2012
@@ -3755,8 +3755,8 @@
} else {
CONVERT_DOUBLE_ARG_CHECKED(from_number, 1);
CONVERT_DOUBLE_ARG_CHECKED(to_number, 2);
- start = FastD2I(from_number);
- end = FastD2I(to_number);
+ start = FastD2IChecked(from_number);
+ end = FastD2IChecked(to_number);
}
RUNTIME_ASSERT(end >= start);
RUNTIME_ASSERT(start >= 0);
@@ -4224,7 +4224,7 @@
return *isolate->factory()->infinity_symbol();
}
CONVERT_DOUBLE_ARG_CHECKED(f_number, 1);
- int f = FastD2I(f_number);
+ int f = FastD2IChecked(f_number);
RUNTIME_ASSERT(f >= 0);
char* str = DoubleToFixedCString(value, f);
MaybeObject* res =
@@ -4249,7 +4249,7 @@
return *isolate->factory()->infinity_symbol();
}
CONVERT_DOUBLE_ARG_CHECKED(f_number, 1);
- int f = FastD2I(f_number);
+ int f = FastD2IChecked(f_number);
RUNTIME_ASSERT(f >= -1 && f <= 20);
char* str = DoubleToExponentialCString(value, f);
MaybeObject* res =
@@ -4274,7 +4274,7 @@
return *isolate->factory()->infinity_symbol();
}
CONVERT_DOUBLE_ARG_CHECKED(f_number, 1);
- int f = FastD2I(f_number);
+ int f = FastD2IChecked(f_number);
RUNTIME_ASSERT(f >= 1 && f <= 21);
char* str = DoubleToPrecisionCString(value, f);
MaybeObject* res =
=======================================
--- /branches/bleeding_edge/test/cctest/test-utils.cc Fri Jan 13 05:09:52
2012
+++ /branches/bleeding_edge/test/cctest/test-utils.cc Mon Jul 30 01:34:26
2012
@@ -55,6 +55,22 @@
CHECK_EQ(-2, -8 >> 2);
CHECK_EQ(-2, static_cast<int8_t>(-8) >> 2);
CHECK_EQ(-2, static_cast<int>(static_cast<intptr_t>(-8) >> 2));
+
+ CHECK_EQ(-1000000, FastD2IChecked(-1000000.0));
+ CHECK_EQ(-1, FastD2IChecked(-1.0));
+ CHECK_EQ(0, FastD2IChecked(0.0));
+ CHECK_EQ(1, FastD2IChecked(1.0));
+ CHECK_EQ(1000000, FastD2IChecked(1000000.0));
+
+ CHECK_EQ(-1000000, FastD2IChecked(-1000000.123));
+ CHECK_EQ(-1, FastD2IChecked(-1.234));
+ CHECK_EQ(0, FastD2IChecked(0.345));
+ CHECK_EQ(1, FastD2IChecked(1.234));
+ CHECK_EQ(1000000, FastD2IChecked(1000000.123));
+
+ CHECK_EQ(INT_MAX, FastD2IChecked(1.0e100));
+ CHECK_EQ(INT_MIN, FastD2IChecked(-1.0e100));
+ CHECK_EQ(INT_MIN, FastD2IChecked(NAN));
}
--
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