+O[no]cross_region_addressing
+O[no]cross_region_addressing
The +O[no]cross_region_addressing option enables [disables] the use of
The default is +Onocross_region_addressing.
NOTE: Using this option may result in reduced runtime performance.
+O[no]datalayout
+O[no]datalayout
The +O[no]datalayout option enables [disables]
The default, in the absence of +Oprofile=use, is +Onodatalayout.
+O[no]dataprefetch
+O[no]dataprefetch
When +Odataprefetch is enabled, the optimizer inserts instructions within innermost loops to explicitly prefetch data from memory into the data cache. Data prefetch instructions are inserted only for data structures referenced within innermost loops using simple loop varying addresses (that is, in a simple arithmetic progression).
Use this option for applications that have high data cache miss overhead.
+Odataprefetch is equivalent to +Odataprefetch=indirect. +Onodataprefetch is equivalent to +Odataprefetch=none.
Usage:
+Odataprefetch=kind
The defined values for kind are:
direct | Enable generation of data prefetch instructions for the benefit of direct memory |
| accesses, but not indirect memory accesses. This is the default at optimization level |
| +O1. |
indirect | Enables the generation of data prefetch instructions for the benefit of both direct and |
| indirect memory accesses. This is the default at optimization levels +O2 and above. |
| It is treated the same as direct at optimization level +O1. |
none | Disables the generation of data prefetch instructions. This is the default at optimization |
| level +O0. |
+O[no]fltacc
+O[no]fltacc=level
The +O[no]fltacc option disables [enables]
If you specify neither +Ofltacc nor +Onofltacc, less optimization is performed than for +Onofltacc. If you specify neither option, the optimizer generates FMA instructions but does not perform any
Specifying +Ofltacc insures the same result as in unoptimized code (+O0).
Usage:
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