From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Fri, 2 May 2025 17:59:13 +0000 (-0300)
Subject: math: Fix UB on lroundl
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c949920ef65aedceaaa679a75cdbaafd110f0cc5;p=thirdparty%2Fglibc.git

math: Fix UB on lroundl

Building with --enable-ubasn triggers:

$ math/test-ldouble-pow
testing long double (without inline functions)
UBSAN: Undefined behaviour in ../sysdeps/ieee754/ldbl-96/s_roundl.c:75:28 left shift of 1 by 31 cannot be represented in type 'int'
Aborted
---

diff --git a/sysdeps/ieee754/ldbl-96/s_roundl.c b/sysdeps/ieee754/ldbl-96/s_roundl.c
index 91d0c445d8..8ec77218fb 100644
--- a/sysdeps/ieee754/ldbl-96/s_roundl.c
+++ b/sysdeps/ieee754/ldbl-96/s_roundl.c
@@ -72,7 +72,7 @@ __roundl (long double x)
 	/* X is integral.  */
 	return x;
 
-      uint32_t j = i1 + (1 << (62 - j0));
+      uint32_t j = i1 + (1U << (62 - j0));
       if (j < i1)
 	{
 	  uint32_t k = i0 + 1;