openwrt/toolchain/musl/patches/055-fix-strtod-int-optimization-in-non-nearest-rounding-mode.patch

From 6ffdc4579ffb34f4aab69ab4c081badabc7c0a9a Mon Sep 17 00:00:00 2001
From: Szabolcs Nagy <nsz@port70.net>
Date: Sun, 4 Sep 2016 04:51:03 +0200
Subject: 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.
---
 src/internal/floatscan.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/internal/floatscan.c b/src/internal/floatscan.c
index 80305ee..ae09852 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 = (KMAX-4)*9;
+				x[KMAX-4] |= 1;
+			}
 		}
 	}
 	if (!gotrad) lrp=dc;
-- 
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