Ok I just had a discussion with adam conrad about this on IRC.
According to him clang currently does assume that armv7 means coretex a8 and that coretex a8 mean full vfpv3 and neon. There is a patch in ubuntu precise/quantal to fix this (26-armv7-not-neon.patch) but it's a pretty big patch and is self-described as a hideous hack. I doubt the release team would accept such a patch at this stage. Therefore it seems the only reasonable thing to do is to select armv6 for clang on armhf in wheezy.
He also alerted me to a patch that disables altivec by default on powerpc since not all powerpc hardware debian supports has altivec. I intend to include this in the proposed NMU, a copy of it is attached.
Since I now have confirmation on what clang does i'll prepare the NMU diff in a day or two.
Description: Make sure PowerPC doesn't default to altivec on Author: Adam Conrad <adcon...@ubuntu.com> Forwarded: no Reviewed-By: Colin Watson <cjwat...@ubuntu.com> Last-Update: 2012-04-24 Index: b/tools/clang/lib/Lex/Makefile =================================================================== --- a/tools/clang/lib/Lex/Makefile +++ b/tools/clang/lib/Lex/Makefile @@ -16,9 +16,5 @@ LIBRARYNAME := clangLex -ifeq ($(ARCH),PowerPC) -CXX.Flags += -maltivec -endif - include $(CLANG_LEVEL)/Makefile
