Fix strtod rounding of half the least subnormal (bug 16151).

diff --git a/ChangeLog b/ChangeLog
index f1e09b1a7ef9efb2b9925e01d804243214e6b66d..c05a9c6143c51d75e98cc5acff0f3986593316ae 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2013-11-13  Joseph Myers  <joseph@codesourcery.com>
+
+       [BZ #16151]
+       * stdlib/strtod_l.c (round_and_return): Do not consider
+       retval[RETURN_LIBM_SIZE - 1] when determining more_bits for an
+       exponent one less than half the least subnormal exponent.
+       * stdlib/test-strtod-round-data: Add more tests.
+       * stdlib/tst-strtod-round.c (tests): Regenerated.
+
 2013-11-13  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>
 
        [BZ #14143]

diff --git a/NEWS b/NEWS
index 3b441241d6548594bb7869037d4c98a6adc3df5a..c6ec27274a7ab51a71f3cfabe80dcca89388c365 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -17,7 +17,8 @@ Version 2.19
   15825, 15844, 15847, 15849, 15855, 15856, 15857, 15859, 15867, 15886,
   15887, 15890, 15892, 15893, 15895, 15897, 15905, 15909, 15917, 15919,
   15921, 15923, 15939, 15948, 15963, 15966, 15985, 15988, 16032, 16034,
-  16036, 16037, 16041, 16071, 16072, 16074, 16078, 16112, 16150, 16153.
+  16036, 16037, 16041, 16071, 16072, 16074, 16078, 16112, 16150, 16151,
+  16153.
 
 * CVE-2012-4412 The strcoll implementation caches indices and rules for
   large collation sequences to optimize multiple passes.  This cache

diff --git a/stdlib/strtod_l.c b/stdlib/strtod_l.c
index 90541cd48fa1ca33c1f079f4ddfb170ece7a5fb3..c1c5c0db4e96094c15d0ddf785d64ccecf14e10d 100644 (file)
--- a/stdlib/strtod_l.c
+++ b/stdlib/strtod_l.c
@@ -228,7 +228,7 @@ round_and_return (mp_limb_t *retval, intmax_t exponent, int negative,
 
          round_limb = retval[RETURN_LIMB_SIZE - 1];
          round_bit = (MANT_DIG - 1) % BITS_PER_MP_LIMB;
-         for (i = 0; i < RETURN_LIMB_SIZE; ++i)
+         for (i = 0; i < RETURN_LIMB_SIZE - 1; ++i)
            more_bits |= retval[i] != 0;
          MPN_ZERO (retval, RETURN_LIMB_SIZE);
        }

diff --git a/stdlib/tst-strtod-round-data b/stdlib/tst-strtod-round-data
index 86d460e3b6f15a654af9affbdb67303cf477a5d8..a6c37677eb31fb739dd25a8d037487ec6b9ffaa2 100644 (file)
--- a/stdlib/tst-strtod-round-data
+++ b/stdlib/tst-strtod-round-data
@@ -109,3 +109,11 @@
 -0x0.7p-1074
 -0x0.7p-16445
 -0x0.7p-16494
+0x1p-150
+0x1p-1075
+0x1p-16446
+0x1p-16495
+-0x1p-150
+-0x1p-1075
+-0x1p-16446
+-0x1p-16495

diff --git a/stdlib/tst-strtod-round.c b/stdlib/tst-strtod-round.c
index 9a440264d0df9f765da7c0e51ef1fdbd956aa880..e7aaed17e8f3ddb0cb1897a0d971edc0e2552880 100644 (file)
--- a/stdlib/tst-strtod-round.c
+++ b/stdlib/tst-strtod-round.c
@@ -7535,6 +7535,294 @@ static const struct test tests[] = {
        -0x0p+0L,
        -0x0p+0L,
        -0x0p+0L),
+  TEST ("0x1p-150",
+       false,
+       0x0p+0f,
+       0x0p+0f,
+       0x0p+0f,
+       0x8p-152f,
+       true,
+       0x4p-152,
+       0x4p-152,
+       0x4p-152,
+       0x4p-152,
+       true,
+       0x4p-152L,
+       0x4p-152L,
+       0x4p-152L,
+       0x4p-152L,
+       true,
+       0x4p-152L,
+       0x4p-152L,
+       0x4p-152L,
+       0x4p-152L,
+       true,
+       0x4p-152L,
+       0x4p-152L,
+       0x4p-152L,
+       0x4p-152L,
+       true,
+       0x4p-152L,
+       0x4p-152L,
+       0x4p-152L,
+       0x4p-152L,
+       true,
+       0x4p-152L,
+       0x4p-152L,
+       0x4p-152L,
+       0x4p-152L),
+  TEST ("0x1p-1075",
+       false,
+       0x0p+0f,
+       0x0p+0f,
+       0x0p+0f,
+       0x8p-152f,
+       false,
+       0x0p+0,
+       0x0p+0,
+       0x0p+0,
+       0x4p-1076,
+       false,
+       0x0p+0L,
+       0x0p+0L,
+       0x0p+0L,
+       0x4p-1076L,
+       true,
+       0x2p-1076L,
+       0x2p-1076L,
+       0x2p-1076L,
+       0x2p-1076L,
+       true,
+       0x2p-1076L,
+       0x2p-1076L,
+       0x2p-1076L,
+       0x2p-1076L,
+       false,
+       0x0p+0L,
+       0x0p+0L,
+       0x0p+0L,
+       0x4p-1076L,
+       true,
+       0x2p-1076L,
+       0x2p-1076L,
+       0x2p-1076L,
+       0x2p-1076L),
+  TEST ("0x1p-16446",
+       false,
+       0x0p+0f,
+       0x0p+0f,
+       0x0p+0f,
+       0x8p-152f,
+       false,
+       0x0p+0,
+       0x0p+0,
+       0x0p+0,
+       0x4p-1076,
+       false,
+       0x0p+0L,
+       0x0p+0L,
+       0x0p+0L,
+       0x4p-1076L,
+       false,
+       0x0p+0L,
+       0x0p+0L,
+       0x0p+0L,
+       0x8p-16448L,
+       true,
+       0x4p-16448L,
+       0x4p-16448L,
+       0x4p-16448L,
+       0x4p-16448L,
+       false,
+       0x0p+0L,
+       0x0p+0L,
+       0x0p+0L,
+       0x4p-1076L,
+       true,
+       0x4p-16448L,
+       0x4p-16448L,
+       0x4p-16448L,
+       0x4p-16448L),
+  TEST ("0x1p-16495",
+       false,
+       0x0p+0f,
+       0x0p+0f,
+       0x0p+0f,
+       0x8p-152f,
+       false,
+       0x0p+0,
+       0x0p+0,
+       0x0p+0,
+       0x4p-1076,
+       false,
+       0x0p+0L,
+       0x0p+0L,
+       0x0p+0L,
+       0x4p-1076L,
+       false,
+       0x0p+0L,
+       0x0p+0L,
+       0x0p+0L,
+       0x8p-16448L,
+       false,
+       0x0p+0L,
+       0x0p+0L,
+       0x0p+0L,
+       0x4p-16448L,
+       false,
+       0x0p+0L,
+       0x0p+0L,
+       0x0p+0L,
+       0x4p-1076L,
+       false,
+       0x0p+0L,
+       0x0p+0L,
+       0x0p+0L,
+       0x4p-16496L),
+  TEST ("-0x1p-150",
+       false,
+       -0x8p-152f,
+       -0x0p+0f,
+       -0x0p+0f,
+       -0x0p+0f,
+       true,
+       -0x4p-152,
+       -0x4p-152,
+       -0x4p-152,
+       -0x4p-152,
+       true,
+       -0x4p-152L,
+       -0x4p-152L,
+       -0x4p-152L,
+       -0x4p-152L,
+       true,
+       -0x4p-152L,
+       -0x4p-152L,
+       -0x4p-152L,
+       -0x4p-152L,
+       true,
+       -0x4p-152L,
+       -0x4p-152L,
+       -0x4p-152L,
+       -0x4p-152L,
+       true,
+       -0x4p-152L,
+       -0x4p-152L,
+       -0x4p-152L,
+       -0x4p-152L,
+       true,
+       -0x4p-152L,
+       -0x4p-152L,
+       -0x4p-152L,
+       -0x4p-152L),
+  TEST ("-0x1p-1075",
+       false,
+       -0x8p-152f,
+       -0x0p+0f,
+       -0x0p+0f,
+       -0x0p+0f,
+       false,
+       -0x4p-1076,
+       -0x0p+0,
+       -0x0p+0,
+       -0x0p+0,
+       false,
+       -0x4p-1076L,
+       -0x0p+0L,
+       -0x0p+0L,
+       -0x0p+0L,
+       true,
+       -0x2p-1076L,
+       -0x2p-1076L,
+       -0x2p-1076L,
+       -0x2p-1076L,
+       true,
+       -0x2p-1076L,
+       -0x2p-1076L,
+       -0x2p-1076L,
+       -0x2p-1076L,
+       false,
+       -0x4p-1076L,
+       -0x0p+0L,
+       -0x0p+0L,
+       -0x0p+0L,
+       true,
+       -0x2p-1076L,
+       -0x2p-1076L,
+       -0x2p-1076L,
+       -0x2p-1076L),
+  TEST ("-0x1p-16446",
+       false,
+       -0x8p-152f,
+       -0x0p+0f,
+       -0x0p+0f,
+       -0x0p+0f,
+       false,
+       -0x4p-1076,
+       -0x0p+0,
+       -0x0p+0,
+       -0x0p+0,
+       false,
+       -0x4p-1076L,
+       -0x0p+0L,
+       -0x0p+0L,
+       -0x0p+0L,
+       false,
+       -0x8p-16448L,
+       -0x0p+0L,
+       -0x0p+0L,
+       -0x0p+0L,
+       true,
+       -0x4p-16448L,
+       -0x4p-16448L,
+       -0x4p-16448L,
+       -0x4p-16448L,
+       false,
+       -0x4p-1076L,
+       -0x0p+0L,
+       -0x0p+0L,
+       -0x0p+0L,
+       true,
+       -0x4p-16448L,
+       -0x4p-16448L,
+       -0x4p-16448L,
+       -0x4p-16448L),
+  TEST ("-0x1p-16495",
+       false,
+       -0x8p-152f,
+       -0x0p+0f,
+       -0x0p+0f,
+       -0x0p+0f,
+       false,
+       -0x4p-1076,
+       -0x0p+0,
+       -0x0p+0,
+       -0x0p+0,
+       false,
+       -0x4p-1076L,
+       -0x0p+0L,
+       -0x0p+0L,
+       -0x0p+0L,
+       false,
+       -0x8p-16448L,
+       -0x0p+0L,
+       -0x0p+0L,
+       -0x0p+0L,
+       false,
+       -0x4p-16448L,
+       -0x0p+0L,
+       -0x0p+0L,
+       -0x0p+0L,
+       false,
+       -0x4p-1076L,
+       -0x0p+0L,
+       -0x0p+0L,
+       -0x0p+0L,
+       false,
+       -0x4p-16496L,
+       -0x0p+0L,
+       -0x0p+0L,
+       -0x0p+0L),
 };
 
 static int