On 01/11/17 17:40, James Greenhalgh wrote: > On Tue, Oct 31, 2017 at 05:07:54PM +0000, Wilco Dijkstra wrote: >> The AArch64 backend currently doesn't set MALLOC_ABI_ALIGNMENT, so >> add this to enable alignment optimizations on malloc pointers. >> >> OK for commit? > > As far as I understand it, because we have 128-bit types, a malloc of > anything greater than 16 bytes would require 16-byte alignment. So, assuming > this macro isn't required to desribe possibly unaligned smaller allocations > (for example 1 byte allocations), this is OK. > > Reviewed-By: James Greenhalgh <james.greenha...@arm.com> > > Thanks, > James > >> >> 2017-10-31 Wilco Dijkstra <wdijk...@arm.com> >> >> * config/aarch64/aarch64.h (MALLOC_ABI_ALIGNMENT): New define. >> -- >> diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h >> index >> 8e7093f0476fa7fed3ba6d6cb008743106d1ff58..159dde7c7134d4d0e5378951d1d8a1d6dab48ba2 >> 100644 >> --- a/gcc/config/aarch64/aarch64.h >> +++ b/gcc/config/aarch64/aarch64.h >> @@ -111,6 +111,9 @@ >> >> #define STRUCTURE_SIZE_BOUNDARY 8 >> >> +/* Heap alignment. */ >> +#define MALLOC_ABI_ALIGNMENT BIGGEST_ALIGNMENT >> + >> /* Defined by the ABI */ >> #define WCHAR_TYPE "unsigned int" >> #define WCHAR_TYPE_SIZE 32
I wonder if it would be safer to define this explicitly as the current value of BIGGEST_ALIGNMENT; then if we ever have to change the latter we won't get silent breakage. R.
