Performance improvement when using "QEMU_FLATTEN" with softfloat type conversions
This bug has been copied automatically from: https://bugs.launchpad.net/qemu/+bug/1892081
Reported by 'Ahmed Karaman (ahmedkrmn)' on 2020-08-18 :
Attached below is a matrix multiplication program for double data types. The program performs the casting operation "(double)rand()" when generating random numbers. This operation calls the integer to float softfloat conversion function "int32_to_float_64". Adding the "QEMU_FLATTEN" attribute to the function definition decreases the instructions per call of the function by about 63%. Attached are before and after performance screenshots from KCachegrind.