On 26/08/11 17:39, Julian Brown wrote: > On Thu, 25 Aug 2011 18:31:21 +0100 > Julian Brown <jul...@codesourcery.com> wrote: > >> On Thu, 25 Aug 2011 16:46:50 +0100 >> Julian Brown <jul...@codesourcery.com> wrote: >> >>> So, OK to apply this version, assuming testing comes out OK? (And >>> the followup patch [2/2], which remains unchanged?) >> >> FWIW, all tests pass, apart from >> gcc.target/arm/volatile-bitfields-3.c, which regresses. The output >> contains: >> >> ldrh r0, [r3, #2] @ unaligned >> >> I believe that, to conform to the ARM EABI, that GCC must use an >> (aligned) ldr in this case. Is that correct? If so, it looks like the >> middle-end bitfield code does not take the setting of >> -fstrict-volatile-bitfields into account. > > This version fixes the last issue, by adding additional checks for > volatile accesses/-fstrict-volatile-bitfields. Tests now show no > regressions. > > OK to apply? >
+ /* On big-endian machines, we count bits from the most significant. + If the bit field insn does not, we must invert. */ It sounds to me like this comment is somewhat out of date now that we have BITS_BIG_ENDIAN; it would be better re-worded to reflect the code as it stands now. Other than that, OK. R. > Thanks, > > Julian > > ChangeLog > > gcc/ > * config/arm/arm.c (arm_override_options): Add unaligned_access > support. > (arm_file_start): Emit attribute for unaligned access as > appropriate. > * config/arm/arm.md (UNSPEC_UNALIGNED_LOAD) > (UNSPEC_UNALIGNED_STORE): Add constants for unspecs. > (insv, extzv): Add unaligned-access support. > (extv): Change to expander. Likewise. > (extzv_t1, extv_regsi): Add helpers. > (unaligned_loadsi, unaligned_loadhis, unaligned_loadhiu) > (unaligned_storesi, unaligned_storehi): New. > (*extv_reg): New (previous extv implementation). > * config/arm/arm.opt (munaligned_access): Add option. > * config/arm/constraints.md (Uw): New constraint. > * expmed.c (store_bit_field_1): Adjust bitfield numbering according > to size of access, not size of unit, when BITS_BIG_ENDIAN != > BYTES_BIG_ENDIAN. Don't use bitfield accesses for > volatile accesses when -fstrict-volatile-bitfields is in effect. > (extract_bit_field_1): Likewise. >
