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| author | Björn Gustavsson <[email protected]> | 2018-09-08 10:20:07 +0200 |
|---|---|---|
| committer | Björn Gustavsson <[email protected]> | 2018-09-12 14:19:06 +0200 |
| commit | b3b195fd104e7052fe31becbab43fccb652f2d0a (patch) | |
| tree | ae513028be67e25924da86d1bebdf7cb5b90ac96 /lib/compiler/src/beam_ssa_opt.erl | |
| parent | 4edd266876f2383ccc33b91a3bbe8550279368f5 (diff) | |
| download | otp-b3b195fd104e7052fe31becbab43fccb652f2d0a.tar.gz otp-b3b195fd104e7052fe31becbab43fccb652f2d0a.tar.bz2 otp-b3b195fd104e7052fe31becbab43fccb652f2d0a.zip | |
beam_ssa_opt: Slightly optimize performance of live optimization
Phi nodes with only literals are fairly common, so it's worthwhile
to optimize this case.
Diffstat (limited to 'lib/compiler/src/beam_ssa_opt.erl')
| -rw-r--r-- | lib/compiler/src/beam_ssa_opt.erl | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/lib/compiler/src/beam_ssa_opt.erl b/lib/compiler/src/beam_ssa_opt.erl index 0bb4a204a2..6d94c38685 100644 --- a/lib/compiler/src/beam_ssa_opt.erl +++ b/lib/compiler/src/beam_ssa_opt.erl @@ -820,11 +820,16 @@ live_opt_phis(Is, L, Live0, LiveMap0) -> LiveMap; [_|_] -> PhiArgs = append([Args || #b_set{args=Args} <- Phis]), - PhiVars = [{P,V} || {#b_var{name=V},P} <- PhiArgs], - PhiLive0 = rel2fam(PhiVars), - PhiLive = [{{L,P},gb_sets:union(gb_sets:from_list(Vs), Live0)} || - {P,Vs} <- PhiLive0], - maps:merge(LiveMap, maps:from_list(PhiLive)) + case [{P,V} || {#b_var{name=V},P} <- PhiArgs] of + [_|_]=PhiVars -> + PhiLive0 = rel2fam(PhiVars), + PhiLive = [{{L,P},gb_sets:union(gb_sets:from_list(Vs), Live0)} || + {P,Vs} <- PhiLive0], + maps:merge(LiveMap, maps:from_list(PhiLive)); + [] -> + %% There were only literals in the phi node(s). + LiveMap + end end. live_opt_blk(#b_blk{is=Is0,last=Last}=Blk, Live0) -> |