From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Mon, 5 May 2025 13:45:15 +0000 (-0300)
Subject: math: Fix UB in ldbl-128 roundl
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c1ffff3c531404a8d64fc12c8df11a68ebd56d13;p=thirdparty%2Fglibc.git

math: Fix UB in ldbl-128 roundl

$ math/test-float128-cospi
testing _Float128 (without inline functions)
UBSAN: Undefined behaviour in ../sysdeps/ieee754/float128/../ldbl-128/s_roundl.c:75:30 left shift of 1 by 63 cannot be represented in type 'long long int'
---

diff --git a/sysdeps/ieee754/ldbl-128/s_roundl.c b/sysdeps/ieee754/ldbl-128/s_roundl.c
index 9a87a463e8..aa02e3c9c6 100644
--- a/sysdeps/ieee754/ldbl-128/s_roundl.c
+++ b/sysdeps/ieee754/ldbl-128/s_roundl.c
@@ -72,7 +72,7 @@ __roundl (_Float128 x)
 	/* X is integral.  */
 	return x;
 
-      uint64_t j = i1 + (1LL << (111 - j0));
+      uint64_t j = i1 + (1ULL << (111 - j0));
       if (j < i1)
 	i0 += 1;
       i1 = j;