On Tue, Nov 14, 2017 at 04:05:12PM +0000, Tamar Christina wrote: > Hi James, > > I have split off the aarch64 bit off from the generic parts and processed > your feedback. > > Attached is the reworked patch. > > Ok for Tunk?
Thanks for the respin, I'm a bit confused by this comment. > diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c > index > e89c8156976cecf200cd67c1e938c8156c1240c4..bc197cc973a2bbc2c263809c7e8ccfbc86309c26 > 100644 > --- a/gcc/config/aarch64/aarch64.c > +++ b/gcc/config/aarch64/aarch64.c > @@ -13974,6 +13974,28 @@ aarch64_expand_movmem (rtx *operands) > base = copy_to_mode_reg (Pmode, XEXP (src, 0)); > src = adjust_automodify_address (src, VOIDmode, base, 0); > > + /* Optimize routines for MEM to REG copies. > + This particular function only handles copying to two > + destination types: 1) a regular register and 2) the stack. > + When writing to a regular register we may end up writting too much in > cases > + where the register already contains a live value or when no data > padding is > + happening so we disallow regular registers to use this new code path. > */ I'm struggling to understand when you'd end up with a struct held in a partial register going through this code path. Maybe the restriction makes sense, can you write a testcase, or show some sample code where this goes wrong (or simplify the comment). Thanks, James
