Developer Guide and Reference

Contents

fp-speculation, Qfp-speculation

Tells the compiler the mode in which to speculate on floating-point operations.

Syntax

Linux:
-fp-speculation
=
mode
Windows:
/Qfp-speculation
:
mode
Arguments
mode
Is the mode for floating-point operations. Possible values are:
fast
Tells the compiler to speculate on floating-point operations.
safe
Tells the compiler to disable speculation if there is a possibility that the speculation may cause a floating-point exception.
strict
Tells the compiler to disable speculation on floating-point operations.
off
This is the same as specifying strict.
Default
-fp-speculation=fast
or
/Qfp-speculation:fast
The compiler speculates on floating-point operations. This is also the behavior when optimizations are enabled. However, if you specify no optimizations (
-O0
on Linux*
;
/Od
on Windows*
), the default is
-fp-speculation=safe
(Linux*)
or
/Qfp-speculation:safe
(Windows*)
.
Description
This option tells the compiler the mode in which to speculate on floating-point operations.
Disabling speculation may prevent the vectorization of some loops containing conditionals. For an example, see the article titled:
Diagnostic 15326: loop was not vectorized: implied FP exception model prevents vectorization
, which is located in https://software.intel.com/content/www/us/en/develop/articles/fdiag15326.html .
IDE Equivalent
Visual Studio:
Optimization > Floating-Point Speculation
Eclipse:
Floating Point > Floating-Point Speculation
Alternate Options
None

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.