On Thu, 8 Aug 2013 15:44:17 +0100 Kyrylo Tkachov <kyrylo.tkac...@arm.com> wrote:
> Hi all, > > The recently added gcc.target/arm/pr58041.c test exposed a bug in the > backend. When compiling for NEON and with -mno-unaligned-access we > end up generating the vld1.64 and vst1.64 instructions instead of > doing the accesses one byte at a time like -mno-unaligned-access > expects. This patch fixes that by enabling the NEON expander and > insns that produce these instructions only when unaligned accesses > are allowed. > > Bootstrapped on arm-linux-gnueabihf. Tested arm-none-eabi on qemu. > > Ok for trunk and 4.8? I'm not sure if this is right, FWIW -- do the instructions in question trap if the CPU is set to disallow unaligned accesses? I thought that control bit only affected ARM core loads & stores, not NEON ones. Not to say the test case you mention isn't broken anyway, for some other reason -- but I don't think disabling NEON movmisalign for !unaligned_access is the right way to fix it. HTH, Julian
