Don't make separate checks for the trailing significand to be non-zero where the check for the quiet bit being 1 already covers it.
The point of the whole expression is to tell inifinities and NaN data apart while also checking for the expected value of the quiet bit, and the quiet bit being 1 in the floating-point datum examined (whether it denotes a qNaN or an sNaN) already makes the datum encoded a NaN rather than an infinity. Signed-off-by: Maciej W. Rozycki <ma...@codesourcery.com> --- Peter, This is the cleanup I mentioned yesterday. It makes 128-bit float handling similar to how 16-bit, 32-bit and 64-bit ones already are handled. This is based on the observation that whenever: (a.high << 1) >= 0xffff000000000000 returns true: a.high & 0x0000ffffffffffffULL also does and therefore the RHS of the && expression always evaluates to true if the LHS does (the reverse is obviously not always the case). It applies on top of: https://patchwork.ozlabs.org/patch/420645/ Maciej qemu-softfloat-float128-nan.diff Index: qemu-git-trunk/fpu/softfloat-specialize.h =================================================================== --- qemu-git-trunk.orig/fpu/softfloat-specialize.h 2014-12-11 21:50:59.000000000 +0000 +++ qemu-git-trunk/fpu/softfloat-specialize.h 2014-12-11 21:57:30.338965285 +0000 @@ -1154,8 +1154,7 @@ int float128_is_quiet_nan(float128 a STA int __attribute__ ((unused)) x, y; x = (((a.high >> 47) & 0xffff) == 0xfffe) && (a.low || (a.high & 0x00007fffffffffffULL)); - y = ((a.high << 1) >= 0xffff000000000000) - && (a.low || (a.high & 0x0000ffffffffffffULL)); + y = (a.high << 1) >= 0xffff000000000000; #if SNAN_BIT_IS_VARIABLE return STATUS(nan2008_mode) ? y : x; #elif SNAN_BIT_IS_ONE @@ -1173,8 +1172,7 @@ int float128_is_quiet_nan(float128 a STA int float128_is_signaling_nan(float128 a STATUS_PARAM) { int __attribute__ ((unused)) x, y; - x = ((a.high << 1) >= 0xffff000000000000) - && (a.low || (a.high & 0x0000ffffffffffffULL)); + x = (a.high << 1) >= 0xffff000000000000; y = (((a.high >> 47) & 0xFFFF) == 0xFFFE) && (a.low || (a.high & LIT64(0x00007FFFFFFFFFFF))); #if SNAN_BIT_IS_VARIABLE
