@setFloatMode

@setFloatMode

@setFloatMode(comptime mode: FloatMode) void

Changes the current scope’s rules about how floating point operations are defined.

• Strict (default) - Floating point operations follow strict IEEE compliance.

• Optimized - Floating point operations may do all of the following:

  • Assume the arguments and result are not NaN. Optimizations are required to retain defined behavior over NaNs, but the value of the result is undefined.
  • Assume the arguments and result are not +/-Inf. Optimizations are required to retain defined behavior over +/-Inf, but the value of the result is undefined.
  • Treat the sign of a zero argument or result as insignificant.
  • Use the reciprocal of an argument rather than perform division.
  • Perform floating-point contraction (e.g. fusing a multiply followed by an addition into a fused multiply-add).
  • Perform algebraically equivalent transformations that may change results in floating point (e.g. reassociate).

This is equivalent to -ffast-math in GCC.

The floating point mode is inherited by child scopes, and can be overridden in any scope. You can set the floating point mode in a struct or module scope by using a comptime block.

FloatMode can be found with @import("std").builtin.FloatMode.

See also:

• Floating Point Operations