| Message ID | 58A2D71E.9080407@foss.arm.com |
|---|---|
| State | New |
| Headers | show |
On 14/02/17 10:08, Kyrill Tkachov wrote: > Hi all, > > Following up from Segher's patch here is the aarch64 implementation of > the new hook. > It forbids speculation of the integer and floating-point division > instructions as well as the > square-root instructions. > > With this patch the fsqrt is not speculated and the preformance on the > code in the PR is improved 3x > on a Cortex-A53. > > Bootstrapped and tested on aarch64-none-linux-gnu. > > Ok for trunk? > > Thanks, > Kyrill > > 2016-02-14 Kyrylo Tkachov <kyrylo.tkachov@arm.com> > > PR rtl-optimization/68664 > * config/aarch64/aarch64.c (aarch64_sched_can_speculate_insn): > New function. > (TARGET_SCHED_CAN_SPECULATE_INSN): Define. > > aarch64-spec.patch OK. R. > > > diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c > index eab719d076358f01023cf8b2a37d3c8edd8d8f1f..f72e4c4423d28af66f3bd8068eeb83060d541839 100644 > --- a/gcc/config/aarch64/aarch64.c > +++ b/gcc/config/aarch64/aarch64.c > @@ -14750,6 +14750,35 @@ aarch64_excess_precision (enum excess_precision_type type) > return FLT_EVAL_METHOD_UNPREDICTABLE; > } > > +/* Implement TARGET_SCHED_CAN_SPECULATE_INSN. Return true if INSN can be > + scheduled for speculative execution. Reject the long-running division > + and square-root instructions. */ > + > +static bool > +aarch64_sched_can_speculate_insn (rtx_insn *insn) > +{ > + switch (get_attr_type (insn)) > + { > + case TYPE_SDIV: > + case TYPE_UDIV: > + case TYPE_FDIVS: > + case TYPE_FDIVD: > + case TYPE_FSQRTS: > + case TYPE_FSQRTD: > + case TYPE_NEON_FP_SQRT_S: > + case TYPE_NEON_FP_SQRT_D: > + case TYPE_NEON_FP_SQRT_S_Q: > + case TYPE_NEON_FP_SQRT_D_Q: > + case TYPE_NEON_FP_DIV_S: > + case TYPE_NEON_FP_DIV_D: > + case TYPE_NEON_FP_DIV_S_Q: > + case TYPE_NEON_FP_DIV_D_Q: > + return false; > + default: > + return true; > + } > +} > + > /* Target-specific selftests. */ > > #if CHECKING_P > @@ -15138,6 +15167,9 @@ aarch64_libgcc_floating_mode_supported_p > #define TARGET_USE_BY_PIECES_INFRASTRUCTURE_P \ > aarch64_use_by_pieces_infrastructure_p > > +#undef TARGET_SCHED_CAN_SPECULATE_INSN > +#define TARGET_SCHED_CAN_SPECULATE_INSN aarch64_sched_can_speculate_insn > + > #undef TARGET_CAN_USE_DOLOOP_P > #define TARGET_CAN_USE_DOLOOP_P can_use_doloop_if_innermost > >
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c index eab719d076358f01023cf8b2a37d3c8edd8d8f1f..f72e4c4423d28af66f3bd8068eeb83060d541839 100644 --- a/gcc/config/aarch64/aarch64.c +++ b/gcc/config/aarch64/aarch64.c @@ -14750,6 +14750,35 @@ aarch64_excess_precision (enum excess_precision_type type) return FLT_EVAL_METHOD_UNPREDICTABLE; } +/* Implement TARGET_SCHED_CAN_SPECULATE_INSN. Return true if INSN can be + scheduled for speculative execution. Reject the long-running division + and square-root instructions. */ + +static bool +aarch64_sched_can_speculate_insn (rtx_insn *insn) +{ + switch (get_attr_type (insn)) + { + case TYPE_SDIV: + case TYPE_UDIV: + case TYPE_FDIVS: + case TYPE_FDIVD: + case TYPE_FSQRTS: + case TYPE_FSQRTD: + case TYPE_NEON_FP_SQRT_S: + case TYPE_NEON_FP_SQRT_D: + case TYPE_NEON_FP_SQRT_S_Q: + case TYPE_NEON_FP_SQRT_D_Q: + case TYPE_NEON_FP_DIV_S: + case TYPE_NEON_FP_DIV_D: + case TYPE_NEON_FP_DIV_S_Q: + case TYPE_NEON_FP_DIV_D_Q: + return false; + default: + return true; + } +} + /* Target-specific selftests. */ #if CHECKING_P @@ -15138,6 +15167,9 @@ aarch64_libgcc_floating_mode_supported_p #define TARGET_USE_BY_PIECES_INFRASTRUCTURE_P \ aarch64_use_by_pieces_infrastructure_p +#undef TARGET_SCHED_CAN_SPECULATE_INSN +#define TARGET_SCHED_CAN_SPECULATE_INSN aarch64_sched_can_speculate_insn + #undef TARGET_CAN_USE_DOLOOP_P #define TARGET_CAN_USE_DOLOOP_P can_use_doloop_if_innermost
Hi all, Following up from Segher's patch here is the aarch64 implementation of the new hook. It forbids speculation of the integer and floating-point division instructions as well as the square-root instructions. With this patch the fsqrt is not speculated and the preformance on the code in the PR is improved 3x on a Cortex-A53. Bootstrapped and tested on aarch64-none-linux-gnu. Ok for trunk? Thanks, Kyrill 2016-02-14 Kyrylo Tkachov <kyrylo.tkachov@arm.com> PR rtl-optimization/68664 * config/aarch64/aarch64.c (aarch64_sched_can_speculate_insn): New function. (TARGET_SCHED_CAN_SPECULATE_INSN): Define.