Developer Guide and Reference

Contents

ansi-alias, Qansi-alias

Enables or disables the use of ANSI aliasing rules in optimizations.

Syntax

Linux:
-ansi-alias
-no-ansi-alias
macOS:
-ansi-alias
-no-ansi-alias
Windows:
/Qansi-alias
/Qansi-alias-
Arguments
None
Default
Windows* systems:
/Qansi-alias
-
ANSI aliasing rules are disabled in optimizations.
Linux* and
macOS*
systems:
-ansi-alias
ANSI aliasing rules are enabled in optimizations.
Description
This option tells the compiler to assume that the program adheres to ISO C Standard aliasability rules.
If your program adheres to the ANSI aliasability rules, this option allows the compiler to optimize more aggressively. If your program does not adhere to these rules, this option may cause the compiler to generate incorrect code.
If you are compiling on a Linux* or an
macOS*
system and your program does not adhere to the ANSI aliasability rules, you can specify
-no-ansi-alias
to ensure program correctness.
When you specify the
[Q]ansi-alias
option, the ansi-alias checker is enabled by default. To disable the ansi-alias checker, you must specify
-no-ansi-alias-check
(Linux* and
macOS*
) or
/Qansi-alias-check-
(Windows*).
Alternate Options
Linux and
macOS*
:
-fstrict-aliasing
Windows: None

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804