#pragma GCC target ("string"...)
attribute((target("STRING"))) was specified for that function. The parenthesis around the options is optional. See Function Attributes, for more information about the target attribute and the attribute syntax. The #pragma GCC target pragma is presently implemented for i386/x86_64, PowerPC, and Nios II targets only.
#pragma GCC optimize ("string"...)
attribute((optimize("STRING"))) was specified for that function. The parenthesis around the options is optional. See Function Attributes, for more information about the optimize attribute and the attribute syntax. The ‘#pragma GCC optimize’ pragma is not implemented in GCC versions earlier than 4.4.
#pragma GCC push_options#pragma GCC pop_options#pragma GCC target’ or ‘#pragma GCC optimize’ and then to pop back to the previous options. The ‘#pragma GCC push_options’ and ‘#pragma GCC pop_options’ pragmas are not implemented in GCC versions earlier than 4.4.
#pragma GCC reset_options#pragma GCC target and #pragma GCC optimize to use the default switches as specified on the command line. The ‘#pragma GCC reset_options’ pragma is not implemented in GCC versions earlier than 4.4.
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Licensed under the GNU Free Documentation License, Version 1.3.
https://gcc.gnu.org/onlinedocs/gcc-4.9.3/gcc/Function-Specific-Option-Pragmas.html