toolchain/musl/patches/048-math-fix-pow-signed-shift-ub.patch

   1 From 688d3da0f1730daddbc954bbc2d27cc96ceee04c Mon Sep 17 00:00:00 2001
   2 From: Szabolcs Nagy <nsz@port70.net>
   3 Date: Tue, 4 Oct 2016 03:58:56 +0200
   4 Subject: math: fix pow signed shift ub
   5
   6 j is int32_t and thus j<<31 is undefined if j==1, so j is changed to
   7 uint32_t locally as a quick fix, the generated code is not affected.
   8
   9 (this is a strict conformance fix, future c standard may allow 1<<31,
  10 see DR 463.  the bug was inherited from freebsd fdlibm, the proper fix
  11 is to use uint32_t for all bit hacks, but that requires more intrusive
  12 changes.)
  13
  14 reported by Daniel Sabogal
  15 ---
  16  src/math/pow.c | 4 ++--
  17  1 file changed, 2 insertions(+), 2 deletions(-)
  18
  19 diff --git a/src/math/pow.c b/src/math/pow.c
  20 index b66f632..3ddc1b6 100644
  21 --- a/src/math/pow.c
  22 +++ b/src/math/pow.c
  23 @@ -125,11 +125,11 @@ double pow(double x, double y)
  24                 else if (iy >= 0x3ff00000) {
  25                         k = (iy>>20) - 0x3ff;  /* exponent */
  26                         if (k > 20) {
  27 -                               j = ly>>(52-k);
  28 +                               uint32_t j = ly>>(52-k);
  29                                 if ((j<<(52-k)) == ly)
  30                                         yisint = 2 - (j&1);
  31                         } else if (ly == 0) {
  32 -                               j = iy>>(20-k);
  33 +                               uint32_t j = iy>>(20-k);
  34                                 if ((j<<(20-k)) == iy)
  35                                         yisint = 2 - (j&1);
  36                         }
  37 --
  38 cgit v0.11.2