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-rw-r--r--lib/hipe/regalloc/hipe_regalloc_prepass.erl21
1 files changed, 13 insertions, 8 deletions
diff --git a/lib/hipe/regalloc/hipe_regalloc_prepass.erl b/lib/hipe/regalloc/hipe_regalloc_prepass.erl
index 5a52e5ad51..c2531bc451 100644
--- a/lib/hipe/regalloc/hipe_regalloc_prepass.erl
+++ b/lib/hipe/regalloc/hipe_regalloc_prepass.erl
@@ -60,8 +60,8 @@
-define(TUNE_TOO_FEW_BBS, 256).
%% Ignore the ra_partitioned option (and do whole function RA instead) when
-%% there are fewer than ?TUNE_MIN_SPLIT_PSEUDOS non-spilled used pseudos.
--define(TUNE_MIN_SPLIT_PSEUDOS, 1024).
+%% there are fewer than ?TUNE_MIN_SPLIT_BBS basic blocks.
+-define(TUNE_MIN_SPLIT_BBS, 384).
%% We present a "pseudo-target" to the register allocator we wrap.
%% Note: all arities are +1 as we're currently using the parameterised module
@@ -145,7 +145,12 @@ regalloc(RegAllocMod, CFG, SpillIndex0, SpillLimit, Target, Options) ->
Liveness),
{Coloring, SpillIndex, Liveness}.
-%% regalloc_initial/6 is allowed to introduce new temporaries, unlike regalloc/6
+%% regalloc_initial/6 is allowed to introduce new temporaries, unlike
+%% regalloc/6.
+%% In order for regalloc/6 to never introduce temporaries, regalloc/6 must never
+%% choose to do split allocation unless regalloc_initial/6 does. This is the
+%% reason that the splitting heuristic is solely based on the number of basic
+%% blocks, which does not change during the register allocation loop.
-spec regalloc_initial(module(), target_cfg(), spillno(), spillno(), module(),
proplists:proplist())
-> {hipe_map(), spillno(), target_cfg(),
@@ -169,12 +174,11 @@ regalloc_1(RegAllocMod, CFG0, SpillIndex0, SpillLimit, Target, Options,
{ScanBBs, Seen, SpillMap, SpillIndex1} =
scan_cfg(CFG0, Liveness, SpillIndex0, Target),
- AllPrecoloured = Target:all_precoloured(),
-
{PartColoring, SpillIndex, NewCFG} =
- case proplists:get_bool(ra_partitioned, Options) of
- true when map_size(Seen) - map_size(SpillMap) - length(AllPrecoloured)
- > ?TUNE_MIN_SPLIT_PSEUDOS ->
+ case proplists:get_bool(ra_partitioned, Options)
+ andalso length(Target:labels(CFG0)) > ?TUNE_MIN_SPLIT_BBS
+ of
+ true ->
regalloc_partitioned(SpillMap, SpillIndex1, SpillLimit, ScanBBs,
CFG0, Target, RegAllocMod, Options);
_ ->
@@ -186,6 +190,7 @@ regalloc_1(RegAllocMod, CFG0, SpillIndex0, SpillLimit, Target, Options,
Coloring = SpillColors ++ PartColoring,
?ASSERT(begin
+ AllPrecoloured = Target:all_precoloured(),
MaxPhys = lists:max(AllPrecoloured) + 1,
Unused = unused(live_pseudos(Seen, SpillMap, MaxPhys),
SpillMap, CFG0, Target),