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authorJoseph Myers <joseph@codesourcery.com>2014-03-29 17:22:14 +0000
committerJoseph Myers <joseph@codesourcery.com>2014-03-29 17:22:14 +0000
commitea6029b19c6004c69a9074bf399091bbfbf58a0c (patch)
treea3f2488c38c5d4438f4dc08166a287825ffb60b1 /math/e_scalb.c
parent56737508002f1759da8d4d9944a8e98e58dce917 (diff)
downloadglibc-ea6029b19c6004c69a9074bf399091bbfbf58a0c.tar.gz
Fix scalb spurious "invalid" exceptions (bug 16770).
This patch fixes bug 16770, spurious "invalid" exceptions from scalb when testing whether the second argument is an integer, by inserting appropriate range checks to determine whether a cast to int is safe. (Note that invalid_fn is a function that handles both nonintegers and large integers, distinguishing them reliably using functions such as __rint; note also that there are no issues with scalb needing to avoid spurious "inexact" exceptions - it's an old-POSIX XSI function, not a standard C function bound to an IEEE 754 operation - although the return value is still fully determined.) Tested x86_64 and x86. [BZ #16770] * math/e_scalb.c (__ieee754_scalb): Check second argument is not too large before casting to int. * math/e_scalbf.c (__ieee754_scalbf): Likewise. * math/e_scalbl.c (__ieee754_scalbl): Likewise. * math/libm-test.inc (scalb_test_data): Add more tests.
Diffstat (limited to 'math/e_scalb.c')
-rw-r--r--math/e_scalb.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/math/e_scalb.c b/math/e_scalb.c
index bddedfa032..146d49e1c3 100644
--- a/math/e_scalb.c
+++ b/math/e_scalb.c
@@ -50,7 +50,7 @@ __ieee754_scalb (double x, double fn)
return x;
return x / -fn;
}
- if (__glibc_unlikely ((double) (int) fn != fn))
+ if (__glibc_unlikely (fabs (fn) >= 0x1p31 || (double) (int) fn != fn))
return invalid_fn (x, fn);
return __scalbn (x, (int) fn);