Intel® C++ Compiler 16.0 User and Reference Guide

prec-div, Qprec-div

Improves precision of floating-point divides.

Syntax

Linux and OS X:

-prec-div

-no-prec-div

Windows:

/Qprec-div

/Qprec-div-

Arguments

None

Default

-prec-div
or/Qprec-div

The compiler uses this method for floating-point divides.

Description

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

With some optimizations, such as -msse2 (Linux* OS) or /arch:SSE2 (Windows* OS), 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* OS and OS X*) or /Qprec-div- (Windows* OS), it enables optimizations that give slightly less precise results than full IEEE division.

IDE Equivalent

None

Alternate Options

None