Linux: warning: optimization flag '-fno-strength-reduce' is not supported [-Wignored-optimization-argument]

[nickdesaulniers]

$ ARCH=m68k CROSS_COMPILE=m68k-linux-gnu- make CC=clang -j71 defconfig
$ ARCH=m68k CROSS_COMPILE=m68k-linux-gnu- make CC=clang -j71
...
clang-12: warning: optimization flag '-fno-strength-reduce' is not supported [-Wignored-optimization-argument]

This is an easy fix/good first issue. The kernel builds with some GCC flag to disable some GCC specific optimization (likely something is broken in that pass, or that pass exposes some brittle code). This flag should be wrapped in the commonly used cc-option macro used in Kbuild. cc @mshockwave.

[mshockwave]

Managed to fix this and #1224 pretty easily, but since this will be a linux kernel change, should I just open a new branch (probably m68k) in this repository to host my changes?

[nathanchance]

Sure. That will make it easy for us to test and review before they get sent to the mailing list.

[nickdesaulniers]

Reopening until this is fixed in the upstream linux kernel proper.