more missing -mcpu values for powerpc

[nickdesaulniers]

See also 4b10306.

So cell, e6500, 405, 464, 476, 860, e300c2, and e300c3 support is missing from clang.

These configs set the -mcpu value in

linux/arch/powerpc/platforms/Kconfig.cputype

Lines 193 to 205 in 83d09ad

	config TARGET_CPU
	string
	depends on TARGET_CPU_BOOL
	default "cell" if CELL_CPU
	default "power5" if POWER5_CPU
	default "power6" if POWER6_CPU
	default "power7" if POWER7_CPU
	default "power8" if POWER8_CPU
	default "power9" if POWER9_CPU
	default "860" if 860_CPU
	default "e300c2" if E300C2_CPU
	default "e300c3" if E300C3_CPU
	default "G4" if G4_CPU

.

cc @nemanjai

[nemanjai]

Since we don't have code generation for these, I would rather not accept them in Clang/LLVM. Are these configurations actually used by anyone or are these just remnants of something that hasn't been used in years? If the latter, can they just be removed?

[nathanchance]

Are these configurations actually used by anyone or are these just remnants of something that hasn't been used in years?

The configurations are still in the tree, so people build them. Whether or not the resulting kernels are actually being booted and used in the wild, let alone with clang, is a completely different story and it is probably hard to figure out, since many hobbyists are not vocal about their usage as long as things stay working. The 32-bit processors are a dying breed obviously (although seemingly still sold in certain applications), so it is probably a waste of resources to try and implement code generation support for them.

For the record, this is being workaround in the kernel by preventing those configurations from being selected:

https://git.kernel.org/linus/4b10306e98456aed03cad75ce467e8b1efdccca0