From 25cca51ed294890d20a3c0290814cd26875db686 Mon Sep 17 00:00:00 2001 From: Ahmad Khalifa Date: Fri, 10 Oct 2025 12:30:52 +0300 Subject: [PATCH] libm: remainder: make sure x is zero Make sure the entirety of x is zero before flipping the sign bit. Otherwise the sign would be wrong for small values of x when x is negative and |n*y| > |x| Reported by: alfredo PR: 251091 Reviewed by: kargl MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D53023 --- lib/msun/src/e_remainder.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/msun/src/e_remainder.c b/lib/msun/src/e_remainder.c index a5fb7141d01..cc6cd320073 100644 --- a/lib/msun/src/e_remainder.c +++ b/lib/msun/src/e_remainder.c @@ -64,8 +64,8 @@ remainder(double x, double p) if(x>=p_half) x -= p; } } - GET_HIGH_WORD(hx,x); - if ((hx&0x7fffffff)==0) hx = 0; + EXTRACT_WORDS(hx, lx, x); + if (((hx&0x7fffffff)|lx) == 0) hx = 0; SET_HIGH_WORD(x,hx^sx); return x; }