POWER: AIX: Make use of power10 optimization #3818

Job	Run time
build (ubuntu-latest, gfortran, cmake)	1h 4m 43s
build (ubuntu-latest, gfortran, make)	26m 1s
msys2 (UCRT64, int32, Release)	1h 23m 59s
build (ubuntu-latest, flang, cmake)	29m 42s
msys2 (UCRT64, int64, Release)	1h 42m 14s
build (ubuntu-latest, flang, make)	15m 31s
cross_build (mips64el, mips64el-linux-gnuabi64, DYNAMIC_ARCH=1 TARGET=GENERIC)	6m 25s
build (macos-latest, gfortran, cmake)	46m 0s
msys2 (MINGW32, int32, Release)	1h 14m 39s
cross_build (riscv64, riscv64-linux-gnu, TARGET=RISCV64_GENERIC)	11m 0s
build (macos-latest, gfortran, make)	39m 20s
msys2 (CLANG64, int32, Release)	45m 3s
cross_build (mipsel, mipsel-linux-gnu, TARGET=MIPS1004K)	5m 47s
msys2 (CLANG64, int64, Release)	43m 47s
msys2 (CLANG32, int32, Release)	36m 35s
cross_build (alpha, alpha-linux-gnu, TARGET=EV4)	4m 24s
msys2 (UCRT64, int32, None, mingw-w64-ucrt-x86_64, fc)	1h 28m 57s
	12h 4m 7s

Provide feedback