> -----Original Message----- > From: Tamar Christina > Sent: Wednesday, May 22, 2024 10:29 AM > To: Richard Sandiford > Cc: gcc-patches@gcc.gnu.org; nd ; Richard Earnshaw > ; Marcus Shawcroft > ; ktkachov@gcc.gnu.org > Subject: RE: [PATCH 2/4]AArch64: add new tuning param and attribute for > enabling conditional early clobber > > > > > Sorry for the bike-shedding, but how about something like "avoid_pred_rmw"? > > (I'm open to other suggestions.) Just looking for something that describes > > either the architecture or the end result that we want to achieve. > > And preferable something fairly short :) > > > > avoid_* would be consistent with the existing "avoid_cross_loop_fma". > > > > > + > > > #undef AARCH64_EXTRA_TUNING_OPTION > > > diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h > > > index > > > bbf11faaf4b4340956094a983f8b0dc2649b2d27..76a18dd511f40ebb58ed12d5 > > 6b46c74084ba7c3c 100644 > > > --- a/gcc/config/aarch64/aarch64.h > > > +++ b/gcc/config/aarch64/aarch64.h > > > @@ -495,6 +495,11 @@ constexpr auto AARCH64_FL_DEFAULT_ISA_MODE = > > AARCH64_FL_SM_OFF; > > > enabled through +gcs. */ > > > #define TARGET_GCS (AARCH64_ISA_GCS) > > > > > > +/* Prefer different predicate registers for the output of a predicated operation > > over > > > + re-using an existing input predicate. */ > > > +#define TARGET_SVE_PRED_CLOBBER (TARGET_SVE \ > > > + && (aarch64_tune_params.extra_tuning_flags \ > > > + & > > AARCH64_EXTRA_TUNE_EARLY_CLOBBER_SVE_PRED_DEST)) > > > > > > /* Standard register usage. */ > > > > > > diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md > > > index > > > dbde066f7478bec51a8703b017ea553aa98be309..1ecd1a2812969504bd5114a > > 53473b478c5ddba82 100644 > > > --- a/gcc/config/aarch64/aarch64.md > > > +++ b/gcc/config/aarch64/aarch64.md > > > @@ -445,6 +445,10 @@ (define_enum_attr "arch" "arches" (const_string > > "any")) > > > ;; target-independent code. > > > (define_attr "is_call" "no,yes" (const_string "no")) > > > > > > +;; Indicates whether we want to enable the pattern with an optional early > > > +;; clobber for SVE predicates. > > > +(define_attr "pred_clobber" "no,yes" (const_string "no")) > > > + > > > ;; [For compatibility with Arm in pipeline models] > > > ;; Attribute that specifies whether or not the instruction touches fp > > > ;; registers. > > > @@ -461,7 +465,8 @@ (define_attr "fp" "no,yes" > > > (define_attr "arch_enabled" "no,yes" > > > (if_then_else > > > (ior > > > - (eq_attr "arch" "any") > > > + (and (eq_attr "arch" "any") > > > + (eq_attr "pred_clobber" "no")) > > > > > > (and (eq_attr "arch" "rcpc8_4") > > > (match_test "AARCH64_ISA_RCPC8_4")) > > > @@ -488,7 +493,10 @@ (define_attr "arch_enabled" "no,yes" > > > (match_test "TARGET_SVE")) > > > > > > (and (eq_attr "arch" "sme") > > > - (match_test "TARGET_SME"))) > > > + (match_test "TARGET_SME")) > > > + > > > + (and (eq_attr "pred_clobber" "yes") > > > + (match_test "TARGET_SVE_PRED_CLOBBER"))) > > > > IMO it'd be bettero handle pred_clobber separately from arch, as a new > > top-level AND: > > > > (and > > (ior > > (eq_attr "pred_clobber" "no") > > (match_test "!TARGET_...")) > > (ior > > ...existing arch tests...)) > > > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues. Ok for master? Thanks, Tamar gcc/ChangeLog: * config/aarch64/aarch64-tuning-flags.def (AVOID_PRED_RMW): New. * config/aarch64/aarch64.h (TARGET_SVE_PRED_CLOBBER): New. * config/aarch64/aarch64.md (pred_clobber): New. (arch_enabled): Use it. -- inline copy of patch -- diff --git a/gcc/config/aarch64/aarch64-tuning-flags.def b/gcc/config/aarch64/aarch64-tuning-flags.def index d5bcaebce770f0b217aac783063d39135f754c77..a9f48f5d3d4ea32fbf53086ba21eab4bc65b6dcb 100644 --- a/gcc/config/aarch64/aarch64-tuning-flags.def +++ b/gcc/config/aarch64/aarch64-tuning-flags.def @@ -48,4 +48,8 @@ AARCH64_EXTRA_TUNING_OPTION ("avoid_cross_loop_fma", AVOID_CROSS_LOOP_FMA) AARCH64_EXTRA_TUNING_OPTION ("fully_pipelined_fma", FULLY_PIPELINED_FMA) +/* Enable is the target prefers to use a fresh register for predicate outputs + rather than re-use an input predicate register. */ +AARCH64_EXTRA_TUNING_OPTION ("avoid_pred_rmw", AVOID_PRED_RMW) + #undef AARCH64_EXTRA_TUNING_OPTION diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h index bbf11faaf4b4340956094a983f8b0dc2649b2d27..e7669e65d7dae5df2ba42c265079b1856a5c382b 100644 --- a/gcc/config/aarch64/aarch64.h +++ b/gcc/config/aarch64/aarch64.h @@ -495,6 +495,11 @@ constexpr auto AARCH64_FL_DEFAULT_ISA_MODE = AARCH64_FL_SM_OFF; enabled through +gcs. */ #define TARGET_GCS (AARCH64_ISA_GCS) +/* Prefer different predicate registers for the output of a predicated operation over + re-using an existing input predicate. */ +#define TARGET_SVE_PRED_CLOBBER (TARGET_SVE \ + && (aarch64_tune_params.extra_tuning_flags \ + & AARCH64_EXTRA_TUNE_AVOID_PRED_RMW)) /* Standard register usage. */ diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md index dbde066f7478bec51a8703b017ea553aa98be309..a7da3c01617eb8411029c7d2e32f13fa2cc1c833 100644 --- a/gcc/config/aarch64/aarch64.md +++ b/gcc/config/aarch64/aarch64.md @@ -445,6 +445,10 @@ (define_enum_attr "arch" "arches" (const_string "any")) ;; target-independent code. (define_attr "is_call" "no,yes" (const_string "no")) +;; Indicates whether we want to enable the pattern with an optional early +;; clobber for SVE predicates. +(define_attr "pred_clobber" "any,no,yes" (const_string "any")) + ;; [For compatibility with Arm in pipeline models] ;; Attribute that specifies whether or not the instruction touches fp ;; registers. @@ -460,7 +464,17 @@ (define_attr "fp" "no,yes" (define_attr "arch_enabled" "no,yes" (if_then_else - (ior + (and + (ior + (and + (eq_attr "pred_clobber" "no") + (match_test "!TARGET_SVE_PRED_CLOBBER")) + (and + (eq_attr "pred_clobber" "yes") + (match_test "TARGET_SVE_PRED_CLOBBER")) + (eq_attr "pred_clobber" "any")) + + (ior (eq_attr "arch" "any") (and (eq_attr "arch" "rcpc8_4") @@ -488,7 +502,7 @@ (define_attr "arch_enabled" "no,yes" (match_test "TARGET_SVE")) (and (eq_attr "arch" "sme") - (match_test "TARGET_SME"))) + (match_test "TARGET_SME")))) (const_string "yes") (const_string "no")))