prec-div, Qprec-div

IDE Equivalent

Architectures

IA-32, Intel® 64 architectures

Syntax

Arguments

None

Default

Description

This option improves precision of floating-point divides. It has a slight impact on speed.

With some optimizations, such as -msse2 (Linux) or /arch:SSE2 (Windows), the compiler may change floating-point division computations into multiplication by the reciprocal of the denominator. For example, A/B is computed as A * (1/B) to improve the speed of the computation.

However, sometimes the value produced by this transformation is not as accurate as full IEEE division. When it is important to have fully precise IEEE division, use this option to disable the floating-point division-to-multiplication optimization. The result is more accurate, with some loss of performance.

If you specify -no-prec-div (Linux and Mac OS X) or /Qprec-div- (Windows), it enables optimizations that give slightly less precise results than full IEEE division.

Alternate Options

None