[llvm-commits] [llvm] r97278 - in /llvm/trunk: lib/Support/APFloat.cpp unittests/ADT/APFloatTest.cpp
John McCall
rjmccall at apple.com
Fri Feb 26 14:20:41 PST 2010
Author: rjmccall
Date: Fri Feb 26 16:20:41 2010
New Revision: 97278
URL: http://llvm.org/viewvc/llvm-project?rev=97278&view=rev
Log:
Make APFloat's string-parsing routines a bit safer against very large exponents.
Modified:
llvm/trunk/lib/Support/APFloat.cpp
llvm/trunk/unittests/ADT/APFloatTest.cpp
Modified: llvm/trunk/lib/Support/APFloat.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APFloat.cpp?rev=97278&r1=97277&r2=97278&view=diff
==============================================================================
--- llvm/trunk/lib/Support/APFloat.cpp (original)
+++ llvm/trunk/lib/Support/APFloat.cpp Fri Feb 26 16:20:41 2010
@@ -17,6 +17,7 @@
#include "llvm/ADT/FoldingSet.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
+#include <limits.h>
#include <cstring>
using namespace llvm;
@@ -2345,11 +2346,24 @@
if (decDigitValue(*D.firstSigDigit) >= 10U) {
category = fcZero;
fs = opOK;
- } else if ((D.normalizedExponent + 1) * 28738
- <= 8651 * (semantics->minExponent - (int) semantics->precision)) {
+
+ /* Check whether the normalized exponent is high enough to overflow
+ max during the log-rebasing in the max-exponent check below. */
+ } else if (D.normalizedExponent - 1 > INT_MAX / 42039) {
+ fs = handleOverflow(rounding_mode);
+
+ /* If it wasn't, then it also wasn't high enough to overflow max
+ during the log-rebasing in the min-exponent check. Check that it
+ won't overflow min in either check, then perform the min-exponent
+ check. */
+ } else if (D.normalizedExponent - 1 < INT_MIN / 42039 ||
+ (D.normalizedExponent + 1) * 28738 <=
+ 8651 * (semantics->minExponent - (int) semantics->precision)) {
/* Underflow to zero and round. */
zeroSignificand();
fs = normalize(rounding_mode, lfLessThanHalf);
+
+ /* We can finally safely perform the max-exponent check. */
} else if ((D.normalizedExponent - 1) * 42039
>= 12655 * semantics->maxExponent) {
/* Overflow and round. */
Modified: llvm/trunk/unittests/ADT/APFloatTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/APFloatTest.cpp?rev=97278&r1=97277&r2=97278&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/APFloatTest.cpp (original)
+++ llvm/trunk/unittests/ADT/APFloatTest.cpp Fri Feb 26 16:20:41 2010
@@ -236,6 +236,13 @@
EXPECT_EQ(2.05e12, APFloat(APFloat::IEEEdouble, "002.05000e12").convertToDouble());
EXPECT_EQ(2.05e+12, APFloat(APFloat::IEEEdouble, "002.05000e+12").convertToDouble());
EXPECT_EQ(2.05e-12, APFloat(APFloat::IEEEdouble, "002.05000e-12").convertToDouble());
+
+ // These are "carefully selected" to overflow the fast log-base
+ // calculations in APFloat.cpp
+ EXPECT_TRUE(APFloat(APFloat::IEEEdouble, "99e99999").isInfinity());
+ EXPECT_TRUE(APFloat(APFloat::IEEEdouble, "-99e99999").isInfinity());
+ EXPECT_TRUE(APFloat(APFloat::IEEEdouble, "1e-99999").isPosZero());
+ EXPECT_TRUE(APFloat(APFloat::IEEEdouble, "-1e-99999").isNegZero());
}
TEST(APFloatTest, fromHexadecimalString) {
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