Gentle Ping! Thanks & Regards Jeevitha
On 10/03/26 11:42 pm, jeevitha wrote: > Hi, > > This patch depends on the -mcpu=future and ISA 3.0 AMO implementation > patches and will be upstreamed after those patches are upstreamed. > These changes have been bootstrapped and regression tested on > powerpc64le-linux. > > This patch adds support for compare-and-swap-equal atomic memory > operations that may be added to a future PowerPC processor. Note that > the names of these functions may change in the future. > > Add _AMO_LD_CS_EQ to the _AMO_LD enum and define four new > compare-and-swap equal helper functions, all guarded by _ARCH_FUTURE. > For non-Future targets, provide error-attribute stubs to emit a > compile-time diagnostic. > > 2026-03-10 Jeevitha Palanisamy <[email protected]> > > gcc/ > * config/rs6000/amo.h (_AMO_LD): Add _AMO_LD_CS_EQ enumerator, > gated on _ARCH_FUTURE. > (amo_lwat_cas_eq, amo_lwat_scas_eq, amo_ldat_cas_eq, > amo_ldat_scas_eq): New compare-and-swap equal helper functions. > (_AMO_ERR_CMPSWP): New macro for error-attribute stubs on > non-Future targets. > > gcc/testsuite/ > * gcc.target/powerpc/amo8.c: New test. > > diff --git a/gcc/config/rs6000/amo.h b/gcc/config/rs6000/amo.h > index 2b52ec755de..0b6997327ae 100644 > --- a/gcc/config/rs6000/amo.h > +++ b/gcc/config/rs6000/amo.h > @@ -44,6 +44,9 @@ enum _AMO_LD { > _AMO_LD_SMIN = 0x07, /* Fetch and Signed Minimum. */ > _AMO_LD_SWAP = 0x08, /* Swap. */ > _AMO_LD_CS_NE = 0x10, /* Compare and Swap Not Equal. */ > +#ifdef _ARCH_FUTURE > + _AMO_LD_CS_EQ = 0x11, /* Compare and Swap Equal. */ > +#endif > _AMO_LD_INC_BOUNDED = 0x18, /* Fetch and Increment Bounded. > */ > _AMO_LD_INC_EQUAL = 0x19, /* Fetch and Increment Equal. */ > _AMO_LD_DEC_BOUNDED = 0x1C /* Fetch and Decrement Bounded. > */ > @@ -159,6 +162,26 @@ _AMO_LD_INCREMENT (amo_ldat_sinc_eq, int64_t, > "ldat", _AMO_LD_INC_EQUAL) > _AMO_LD_INCREMENT (amo_ldat_sinc_bounded, int64_t, "ldat", > _AMO_LD_INC_BOUNDED) > _AMO_LD_DECREMENT (amo_ldat_sdec_bounded, int64_t, "ldat", > _AMO_LD_DEC_BOUNDED) > > +/* Future specific compare-and-swap equal operations. */ > +#ifdef _ARCH_FUTURE > +_AMO_LD_CMPSWP (amo_lwat_cas_eq, uint32_t, "lwat", _AMO_LD_CS_EQ) > +_AMO_LD_CMPSWP (amo_lwat_scas_eq, int32_t, "lwat", _AMO_LD_CS_EQ) > +_AMO_LD_CMPSWP (amo_ldat_cas_eq, uint64_t, "ldat", _AMO_LD_CS_EQ) > +_AMO_LD_CMPSWP (amo_ldat_scas_eq, int64_t, "ldat", _AMO_LD_CS_EQ) > +#else /* ! _ARCH_FUTURE */ > +/* Dummy declarations with GCC error attribute: Triggers custom error on > use. */ > +#define _AMO_ERR_CMPSWP(NAME, TYPE) \ > +extern TYPE \ > +NAME (TYPE *_ADDR, TYPE _COND, TYPE _VALUE) \ > + __attribute__ ((error (#NAME " requires -mcpu=future; not available on > Power10 or earlier"))); > + > +_AMO_ERR_CMPSWP (amo_lwat_cas_eq, uint32_t) > +_AMO_ERR_CMPSWP (amo_lwat_scas_eq, int32_t) > +_AMO_ERR_CMPSWP (amo_ldat_cas_eq, uint64_t) > +_AMO_ERR_CMPSWP (amo_ldat_scas_eq, int64_t) > +#undef _AMO_ERR_CMPSWP > +#endif > + > /* Enumeration of the STWAT/STDAT sub-opcodes. */ > enum _AMO_ST { > _AMO_ST_ADD = 0x00, /* Store Add. */ > diff --git a/gcc/testsuite/gcc.target/powerpc/amo8.c > b/gcc/testsuite/gcc.target/powerpc/amo8.c > new file mode 100644 > index 00000000000..8c68fd290bc > --- /dev/null > +++ b/gcc/testsuite/gcc.target/powerpc/amo8.c > @@ -0,0 +1,34 @@ > +/* { dg-do compile } */ > +/* { dg-options "-mdejagnu-cpu=future -O2" } */ > + > +#include <amo.h> > +#include <stdint.h> > + > +/* Verify Future ISA atomic memory compare-and-swap equal operations. */ > + > +uint32_t > +do_lw_cs_eq (uint32_t *mem, uint32_t cond, uint32_t value) > +{ > + return amo_lwat_cas_eq (mem, cond, value); > +} > + > +int32_t > +do_lw_scs_eq (int32_t *mem, int32_t cond, int32_t value) > +{ > + return amo_lwat_scas_eq (mem, cond, value); > +} > + > +uint64_t > +do_ld_cs_eq (uint64_t *mem, uint64_t cond, uint64_t value) > +{ > + return amo_ldat_cas_eq (mem, cond, value); > +} > + > +int64_t > +do_ld_scs_eq (int64_t *mem, int64_t cond, int64_t value) > +{ > + return amo_ldat_scas_eq (mem, cond, value); > +} > + > +/* { dg-final { scan-assembler-times {\mlwat\M} 2 } } */ > +/* { dg-final { scan-assembler-times {\mldat\M} 2 } } */ >
