Committed.
On Fri, 03 Nov 2017 08:34:38 PDT (-0700), Palmer Dabbelt wrote: > From: Andrew Waterman <and...@sifive.com> > > When implementing the RISC-V port, I took the name of this macro at > face value. It appears we were mistaken in what this means, here's a > quote from the SPARC port that better describes what SLOW_BYTE_ACCESS > does > > /* Nonzero if access to memory by bytes is slow and undesirable. > For RISC chips, it means that access to memory by bytes is no > better than access by words when possible, so grab a whole word > and maybe make use of that. */ > > I've added the comment to our port as well. > > See https://gcc.gnu.org/ml/gcc/2017-08/msg00202.html for more > discussion. Thanks to Michael Clark and Andrew Pinski for the help! > > gcc/ChangeLog > > 2017-10-03 Andrew Waterman <and...@sifive.com> > > * config/riscv/riscv.h (SLOW_BYTE_ACCESS): Change to 1. > --- > gcc/config/riscv/riscv.h | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h > index e53555efe82f..a802a3f8cbbb 100644 > --- a/gcc/config/riscv/riscv.h > +++ b/gcc/config/riscv/riscv.h > @@ -615,7 +615,12 @@ typedef struct { > #define MOVE_MAX UNITS_PER_WORD > #define MAX_MOVE_MAX 8 > > -#define SLOW_BYTE_ACCESS 0 > +/* The SPARC port says: > + Nonzero if access to memory by bytes is slow and undesirable. > + For RISC chips, it means that access to memory by bytes is no > + better than access by words when possible, so grab a whole word > + and maybe make use of that. */ > +#define SLOW_BYTE_ACCESS 1 > > #define SHIFT_COUNT_TRUNCATED 1
