Merge pull request #980 from maxmarsc/master

Fixed `constants::signmask` for GCC when using `ffast-math`

Author: JohanMabille

include/xsimd/arch/generic/xsimd_generic_math.hpp

@@ -95,12 +95,12 @@ namespace xsimd
         template <class A>
         inline batch<float, A> bitofsign(batch<float, A> const& self, requires_arch<generic>) noexcept
         {
-            return self & constants::minuszero<batch<float, A>>();
+            return self & constants::signmask<batch<float, A>>();
         }
         template <class A>
         inline batch<double, A> bitofsign(batch<double, A> const& self, requires_arch<generic>) noexcept
         {
-            return self & constants::minuszero<batch<double, A>>();
+            return self & constants::signmask<batch<double, A>>();
         }
 
         // bitwise_cast

include/xsimd/arch/xsimd_constants.hpp

@@ -56,6 +56,11 @@ namespace xsimd
         return bit_cast<double>((uint64_t)DOUBLE);      \
     }
 
+// Under fast-math, GCC might replace signmask (minus zero) by zero
+#if defined(__FAST_MATH__) && defined(__GNUC__) && !defined(__clang__)
+#pragma GCC push_options
+#pragma GCC optimize("signed-zeros")
+#endif
         XSIMD_DEFINE_CONSTANT(infinity, (std::numeric_limits<float>::infinity()), (std::numeric_limits<double>::infinity()))
         XSIMD_DEFINE_CONSTANT(invlog_2, 1.442695040888963407359924681001892137426645954152986f, 1.442695040888963407359924681001892137426645954152986)
         XSIMD_DEFINE_CONSTANT_HEX(invlog_2hi, 0x3fb8b000, 0x3ff7154765200000)
@@ -79,7 +84,6 @@ namespace xsimd
         XSIMD_DEFINE_CONSTANT(minlog2, -127.0f, -1023.)
         XSIMD_DEFINE_CONSTANT(minlog10, -37.89999771118164f, -308.2547155599167)
         XSIMD_DEFINE_CONSTANT(minusinfinity, (-infinity<float>()), (-infinity<double>()))
-        XSIMD_DEFINE_CONSTANT(minuszero, -0.0f, -0.0)
         XSIMD_DEFINE_CONSTANT_HEX(nan, 0xffffffff, 0xffffffffffffffff)
         XSIMD_DEFINE_CONSTANT_HEX(oneosqrteps, 0x453504f3, 0x4190000000000000)
         XSIMD_DEFINE_CONSTANT_HEX(oneotwoeps, 0x4a800000, 0x4320000000000000)
@@ -104,6 +108,9 @@ namespace xsimd
         XSIMD_DEFINE_CONSTANT_HEX(twoopi, 0x3f22f983, 0x3fe45f306dc9c883)
         XSIMD_DEFINE_CONSTANT(twotonmb, 8388608.0f, 4503599627370496.0)
         XSIMD_DEFINE_CONSTANT_HEX(twotonmbo3, 0x3ba14518, 0x3ed428a2f98d7286)
+#if defined(__FAST_MATH__) && defined(__GNUC__) && !defined(__clang__)
+#pragma GCC pop_options
+#endif
 
 #undef XSIMD_DEFINE_CONSTANT
 #undef XSIMD_DEFINE_CONSTANT_HEX