commit 536103221911692d546d7325435812c29bb32ff1 Author: Nick Mathewson nickm@torproject.org Date: Mon Jul 3 10:59:31 2017 -0400

Fix -Wfloat-conversion C warnings on mingw in clamp_double_to_int64.

We just have to suppress these warnings: Mingw's math.h uses gcc's __builtin_choose_expr() facility to declare isnan, isfinite, and signbit. But as implemented in at least some versions of gcc, __builtin_choose_expr() can generate type warnings even from branches that are not taken.

Fixes bug 22801; bugfix on 0.2.8.1-alpha. --- changes/bug22801 | 5 +++++ src/common/util.c | 12 ++++++++++++ 2 files changed, 17 insertions(+)

diff --git a/changes/bug22801 b/changes/bug22801 new file mode 100644 index 0000000..7edc79b --- /dev/null +++ b/changes/bug22801 @@ -0,0 +1,5 @@ + o Minor bugfixes (compilation): + - When building with certain versions the mingw C header files, avoid + float-conversion warnings when calling the C functions isfinite(), + isnan(), and signbit(). Fixes bug 22801; bugfix on 0.2.8.1-alpha. + diff --git a/src/common/util.c b/src/common/util.c index f3effe0..b2b9761 100644 --- a/src/common/util.c +++ b/src/common/util.c @@ -5537,6 +5537,15 @@ clamp_double_to_int64(double number) { int exp;

+#if defined(__MINGW32__) || defined(__MINGW64__) +/* + Mingw's math.h uses gcc's __builtin_choose_expr() facility to declare + isnan, isfinite, and signbit. But as implemented in at least some + versions of gcc, __builtin_choose_expr() can generate type warnings + even from branches that are not taken. So, suppress those warnings. +*/ +DISABLE_GCC_WARNING(float-conversion) +#endif /* NaN is a special case that can't be used with the logic below. */ if (isnan(number)) { return 0; @@ -5562,5 +5571,8 @@ clamp_double_to_int64(double number)

/* Handle infinities and finite numbers with magnitude >= 2^63. */ return signbit(number) ? INT64_MIN : INT64_MAX; +#if defined(__MINGW32__) || defined(__MINGW64__) +ENABLE_GCC_WARNING(float-conversion) +#endif }