syslinux/trunk/0018-prevent-pow-optimization.patch

   1 From: Lukas Schwaighofer <lukas@schwaighofer.name>
   2 Date: Tue, 26 Feb 2019 23:13:58 +0100
   3 Subject: Prevent optimizing the pow() function
   4
   5 With the current GCC 8.2.0 from Debian, a section of code calling pow() in
   6 zzjson_parse.c is turned into a sequence calling exp(). Since no exp()
   7 implementation is available in syslinux those optimizations need to be
   8 disabled.
   9 ---
  10  com32/gpllib/zzjson/zzjson_parse.c | 6 +++++-
  11  1 file changed, 5 insertions(+), 1 deletion(-)
  12
  13 diff --git a/com32/gpllib/zzjson/zzjson_parse.c b/com32/gpllib/zzjson/zzjson_parse.c
  14 index ecb6f61..e66a9d8 100644
  15 --- a/com32/gpllib/zzjson/zzjson_parse.c
  16 +++ b/com32/gpllib/zzjson/zzjson_parse.c
  17 @@ -138,6 +138,10 @@ static ZZJSON *parse_string2(ZZJSON_CONFIG *config) {
  18      return zzjson;
  19  }
  20
  21 +static double __attribute__((optimize("O0"))) pow_noopt(double x, double y) {
  22 +       return pow(x, y);
  23 +}
  24 +
  25  static ZZJSON *parse_number(ZZJSON_CONFIG *config) {
  26      ZZJSON *zzjson;
  27      unsigned long long ival = 0, expo = 0;
  28 @@ -213,7 +217,7 @@ skipexpo:
  29      if (dbl) {
  30          dval = sign * (long long) ival;
  31          dval += sign * frac;
  32 -        dval *= pow(10.0, (double) signexpo * expo);
  33 +        dval *= pow_noopt(10.0, (double) signexpo * expo);
  34      }
  35
  36      zzjson = config->calloc(1, sizeof(ZZJSON));