Make APFloat's string-parsing routines a bit safer against very large exponents.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97278 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index 1e6d22f..f90973f 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -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. */