Default Compiler Options

Some compiler options are only available on certain systems. In the following table, these options are indicated with labels as follows:

Label Meaning
i32 Option available on IA-32-based systems
i32em Option available on IntelŪ Extended Memory 64 Technology (IntelŪ EM64T) systems
i64 Option available on ItaniumŪ-based systems
Option Description
-alias_args Enable C/C++ rule that function arguments may be aliased.
-ansi_alias Enable use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
-complex_limited_range- Disable the use of the basic algebraic expansions of some complex arithmetic operations.
-falias Assume aliasing in program.
-ffnalias Assume aliasing within functions.
-frtti Support for RTTI.
-fverbose-asm Produce assembly file with compiler comments (requires -S).
(i32 only)
Optimizes for IntelŪ Pentium® 4 processor.
(i64 only)
Optimizes for IntelŪ ItaniumŪ 2 processor.
-O1 Same as -O2 on IA-32. Same as -O on Itanium-based systems.
(i32, i32em)
Set internal floating-point precision to 64-bit significand.
-prefetch Enables the insertion of software prefetching by the compiler.
-sox- Disable saving of compiler options and version in the executable.
-std=gnu89 ISO C90 plus GNU extensions. Includes some C99 features.
(i64 only)
Target optimization to the Itanium 2 processor.
(i32 only)
Target optimization to the Pentium 4 2 processor.
-w1 Display warnings and errors.