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| author | Justus Fasse <justus.fasse@etu.univ-grenoble-alpes.fr> | 2021-08-10 23:47:42 +0200 |
|---|---|---|
| committer | Justus Fasse <justus.fasse@etu.univ-grenoble-alpes.fr> | 2021-08-10 23:51:16 +0200 |
| commit | 21edfe0d156d92777af862fbbb68aad3758cd5fe (patch) | |
| tree | eddfc7631ea87a36e4542a7f275952259643fd6f | |
| parent | 549cc16118d0c1f80084016c4a0d73a5d43dc221 (diff) | |
| download | compcert-kvx-21edfe0d156d92777af862fbbb68aad3758cd5fe.tar.gz compcert-kvx-21edfe0d156d92777af862fbbb68aad3758cd5fe.zip | |
Do not incur latency hit for the fake-read of the memory by a side exit
| -rw-r--r-- | aarch64/PrepassSchedulingOracle.ml | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/aarch64/PrepassSchedulingOracle.ml b/aarch64/PrepassSchedulingOracle.ml index 49e4870c..db62287d 100644 --- a/aarch64/PrepassSchedulingOracle.ml +++ b/aarch64/PrepassSchedulingOracle.ml @@ -455,6 +455,18 @@ let get_fake_deps_liveness (opweights : opweights) (seqa : (instruction*Regset.t end; last_mem_reads := i :: !last_mem_reads end + and add_input_mem_formality i = + if not (use_alias_analysis ()) + then + begin + begin + (* Read after write *) + match !last_mem_write with + | None -> () + | Some j -> add_constraint j i 0 + end; + last_mem_reads := i :: !last_mem_reads + end and add_output_mem i = if not (use_alias_analysis ()) then @@ -588,7 +600,7 @@ let get_fake_deps_liveness (opweights : opweights) (seqa : (instruction*Regset.t failwith "Ibuiltin" | Icond(cond, inputs, _, _, _) -> set_branch i; - add_input_mem i; + add_input_mem_formality i; add_input_regs i inputs | Ijumptable(input, _) -> set_branch i; @@ -647,7 +659,9 @@ let get_fake_deps_liveness_stores (opweights : opweights) (seqa : (instruction*R if not (use_alias_analysis ()) then begin - List.iter (fun j -> add_constraint j i 1) !writes_to_commit; + (* cf. add_input_mem_formality *) + (* We can compensate for movement across a single branch, but not two. *) + List.iter (fun j -> add_constraint j i 0) !writes_to_commit; writes_to_commit := !last_mem_writes; last_mem_writes := (match !last_mem_writes with | [] -> [] |