From: Szabolcs Nagy <nsz@port70.net>
Date: Sun, 4 Sep 2016 02:51:03 +0000 (+0200)
Subject: fix strtod int optimization in non-nearest rounding mode
X-Git-Tag: v1.1.16~43
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=6ffdc4579ffb34f4aab69ab4c081badabc7c0a9a;p=oweals%2Fmusl.git

fix strtod int optimization in non-nearest rounding mode

the mid-sized integer optimization relies on lnz set up properly
to mark the last non-zero decimal digit, but this was not done
if the non-zero digit lied outside the KMAX digits of the base
10^9 number representation.

so if the fractional part was a very long list of zeros (>2048*9 on
x86) followed by non-zero digits then the integer optimization could
kick in discarding the tiny non-zero fraction which can mean wrong
result on non-nearest rounding mode.

strtof, strtod and strtold were all affected.
---

diff --git a/src/internal/floatscan.c b/src/internal/floatscan.c
index 80305ee6..ae098526 100644
--- a/src/internal/floatscan.c
+++ b/src/internal/floatscan.c
@@ -110,7 +110,10 @@ static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int po
 			gotdig=1;
 		} else {
 			dc++;
-			if (c!='0') x[KMAX-4] |= 1;
+			if (c!='0') {
+				lnz = dc;
+				x[KMAX-4] |= 1;
+			}
 		}
 	}
 	if (!gotrad) lrp=dc;