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

   1 From 6ffdc4579ffb34f4aab69ab4c081badabc7c0a9a Mon Sep 17 00:00:00 2001
   2 From: Szabolcs Nagy <nsz@port70.net>
   3 Date: Sun, 4 Sep 2016 04:51:03 +0200
   4 Subject: fix strtod int optimization in non-nearest rounding mode
   5
   6 the mid-sized integer optimization relies on lnz set up properly
   7 to mark the last non-zero decimal digit, but this was not done
   8 if the non-zero digit lied outside the KMAX digits of the base
   9 10^9 number representation.
  10
  11 so if the fractional part was a very long list of zeros (>2048*9 on
  12 x86) followed by non-zero digits then the integer optimization could
  13 kick in discarding the tiny non-zero fraction which can mean wrong
  14 result on non-nearest rounding mode.
  15
  16 strtof, strtod and strtold were all affected.
  17 ---
  18  src/internal/floatscan.c | 5 ++++-
  19  1 file changed, 4 insertions(+), 1 deletion(-)
  20
  21 diff --git a/src/internal/floatscan.c b/src/internal/floatscan.c
  22 index 80305ee..ae09852 100644
  23 --- a/src/internal/floatscan.c
  24 +++ b/src/internal/floatscan.c
  25 @@ -110,7 +110,10 @@ static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int po
  26                         gotdig=1;
  27                 } else {
  28                         dc++;
  29 -                       if (c!='0') x[KMAX-4] |= 1;
  30 +                       if (c!='0') {
  31 +                               lnz = (KMAX-4)*9;
  32 +                               x[KMAX-4] |= 1;
  33 +                       }
  34                 }
  35         }
  36         if (!gotrad) lrp=dc;
  37 --
  38 cgit v0.11.2