+Ofltacc disables optimizations that change the order of expression evaluation and therefore may affect the accuracy of the result. The +Ofltaccoption also disables fusing.
NOTE: +Ofltacc is the same as +Ofltacc=strict. +Onofltacc is the same as +Ofltacc=relaxed.
Table
Table 18 Optimizations performed by +O[no]fltacc
+O[no]fltacc | Expression reordering? |
| FMA? |
|
|
|
|
| No |
| Yes |
|
|
|
|
+Ofltacc | No |
| No |
|
|
|
|
+Onofltacc | Yes |
| Yes |
|
|
|
|
|
| ||
+O[no]fltacc=[strictdefaultlimitedrelaxed] | Control the level of floating point | ||
|
| optimizations that the compiler may | |
|
| perform. The defined values for optlevel | |
|
| are: | |
|
| ||
|
| optimization that can result in numerical | |
|
| differences. This is the same as | |
|
| +Ofltacc. | |
|
|
| |
|
| ||
|
| fused | |
|
| any other floating point optimization that | |
|
| can result in numerical differences. | |
|
| ||
|
| floating point optimizations which may | |
|
| affect the generation and propogation of | |
|
| infinities, NaNs, and the sign of zero. | |
|
| Also implies +Ocxlimitedrange. | |
|
| ||
|
| optimizations allowed by limited, permits | |
|
| optimizations, such as reordering of | |
|
| expressions, even if parenthesized, that | |
|
| may affect a rounding error. This is the | |
|
| same as +Onofltacc. Also implies | |
|
| +Ocxlimitedrange. | |
|
| ||
+Ofrequently_called=function1[,function2...] | The named functions are assumed to be | ||
|
| frequently called. This option overrides | |
|
| any information in a profile database. | |
|
|
| |
+Ofrequently_called:filename |
| The file indicated by filename contains a | |
|
| list of function names, separated by | |
|
| spaces or newlines. These functions are | |
|
| assumed to be frequently called. This | |
|
| option overrides any information in a | |
|
| profile database. | |
|
|
| |
+O[no]info |
| +Oinfo causes the compiler to display | |
|
| informational messages about the | |
|
| optimization process. The +Oinfo option | |
|
| provides feedback that can help you to | |
|
|
|
|
43 |