3.6.6 Options for Controlling Optimization

The options tabulated below control compiler optimizations and are described in the sections that follow.

Table 3-16. General Optimization Options
Option (links to explanatory section)	License	Builds with
`-O0`	All	No optimizations (default)
`-O1` `-O`	All	Optimization level 1
`-O2`	All	Optimization level 2
`-O3`	PRO only	Speed-orientated Optimizations
`-Og`	All	Better debugging
`-Os`	PRO only	Size-orientated optimizations
`-f[no-]data-sections`	All	Each data object assigned to its own section
`-f[no-]fat-lto-objects`	PRO only	Both object code and an internal representation written to the object files
`-f[no-]function-sections`	All	Each function assigned to its own section
`-f[no-]lto`	PRO only	The standard link-time optimizer
`-flto-partition=algorithm`	PRO only	The specified algorithm to partition object files when running the link-time optimizer
`-f[no-]omit-frame-pointer`	All	The stack pointer used in preference to the frame pointer
`-mno-pa-on-file=filename`	PRO	Procedural abstraction disabled for the specified file
`-mno-pa-on-function=function`	PRO	Procedural abstraction disabled for the specified function
`-mno-pa-outline-calls`	PRO	Procedural abstraction disabled across function calls
`-f[no-]section-anchors`	All	Static objects accessed relative to one symbol
`-f[no-]unroll-[all-]loops`	All	Loops unrolled to improve execution speed
`-f[no-]use-linker-plugin`	PRO only	A linker plugin with link-time optimizations
`-f[no-]whole-program`	PRO only	The whole-program optimizations
`-m[no-]gas-isr-prologues`	All	Optimized context switch code for small interrupt service routines
`-mpa-callcost-shortcall`	PRO only	More aggressive procedural abstraction
`-mpa-iterations=n`	PRO only	The specified number of proceedural abstraction iterations
`--nofallback`	All	Only the selected optimization level and with no license-imposed fall back to a lesser level