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-rw-r--r--lib/compiler/src/beam_type.erl27
-rw-r--r--lib/compiler/test/guard_SUITE.erl12
2 files changed, 26 insertions, 13 deletions
diff --git a/lib/compiler/src/beam_type.erl b/lib/compiler/src/beam_type.erl
index 8dd6e5f1c6..26c933481a 100644
--- a/lib/compiler/src/beam_type.erl
+++ b/lib/compiler/src/beam_type.erl
@@ -329,27 +329,27 @@ build_alloc(Words, Floats) -> {alloc,[{words,Words},{floats,Floats}]}.
%% flt_liveness([Instruction]) -> [Instruction]
%% (Re)calculate the number of live registers for each heap allocation
-%% function. We base liveness of the number of live registers at
-%% entry to the instruction sequence.
+%% function. We base liveness of the number of register map at the
+%% beginning of the instruction sequence.
%%
%% A 'not_possible' term will be thrown if the set of live registers
%% is not continous at an allocation function (e.g. if {x,0} and {x,2}
%% are live, but not {x,1}).
-flt_liveness([{'%live',Live,_}=LiveInstr|Is]) ->
- flt_liveness_1(Is, init_regs(Live), [LiveInstr]).
+flt_liveness([{'%live',_Live,Regs}=LiveInstr|Is]) ->
+ flt_liveness_1(Is, Regs, [LiveInstr]).
-flt_liveness_1([{set,Ds,Ss,{alloc,_,Alloc}}|Is], Regs0, Acc) ->
- Live = live_regs(Regs0),
+flt_liveness_1([{set,Ds,Ss,{alloc,Live0,Alloc}}|Is], Regs0, Acc) ->
+ Live = min(Live0, live_regs(Regs0)),
I = {set,Ds,Ss,{alloc,Live,Alloc}},
- Regs = foldl(fun(R, A) -> set_live(R, A) end, Regs0, Ds),
+ Regs1 = init_regs(Live),
+ Regs = x_live(Ds, Regs1),
flt_liveness_1(Is, Regs, [I|Acc]);
flt_liveness_1([{set,Ds,_,_}=I|Is], Regs0, Acc) ->
- Regs = foldl(fun(R, A) -> set_live(R, A) end, Regs0, Ds),
+ Regs = x_live(Ds, Regs0),
flt_liveness_1(Is, Regs, [I|Acc]);
-flt_liveness_1([{'%live',_,_}=I|Is], Regs, Acc) ->
- flt_liveness_1(Is, Regs, [I|Acc]);
-flt_liveness_1([], _Regs, Acc) -> reverse(Acc).
+flt_liveness_1([{'%live',_,_}], _Regs, Acc) ->
+ reverse(Acc).
init_regs(Live) ->
(1 bsl Live) - 1.
@@ -364,8 +364,9 @@ live_regs_1(R, N) ->
1 -> live_regs_1(R bsr 1, N+1)
end.
-set_live({x,X}, Regs) -> Regs bor (1 bsl X);
-set_live(_, Regs) -> Regs.
+x_live([{x,N}|Rs], Regs) -> x_live(Rs, Regs bor (1 bsl N));
+x_live([_|Rs], Regs) -> x_live(Rs, Regs);
+x_live([], Regs) -> Regs.
%% update(Instruction, TypeDb) -> NewTypeDb
%% Update the type database to account for executing an instruction.
diff --git a/lib/compiler/test/guard_SUITE.erl b/lib/compiler/test/guard_SUITE.erl
index 8db47ffa40..08279d9408 100644
--- a/lib/compiler/test/guard_SUITE.erl
+++ b/lib/compiler/test/guard_SUITE.erl
@@ -1802,6 +1802,12 @@ bad_guards(Config) when is_list(Config) ->
fc(catch bad_guards_2(#{a=>0,b=>0}, [x])),
fc(catch bad_guards_2(not_a_map, [x])),
fc(catch bad_guards_2(42, [x])),
+
+ fc(catch bad_guards_3(#{a=>0,b=>0}, [])),
+ fc(catch bad_guards_3(#{a=>0,b=>0}, [x])),
+ fc(catch bad_guards_3(not_a_map, [x])),
+ fc(catch bad_guards_3(42, [x])),
+
ok.
%% beam_bool used to produce GC BIF instructions whose
@@ -1813,6 +1819,12 @@ bad_guards_1(X, [_]) when {{X}}, -X ->
bad_guards_2(M, [_]) when M#{a := 0, b => 0}, map_size(M) ->
ok.
+%% beam_type used to produce an GC BIF instruction whose Live operand
+%% included uninitialized registers.
+
+bad_guards_3(M, [_]) when is_map(M) andalso M#{a := 0, b => 0}, length(M) ->
+ ok.
+
%% Call this function to turn off constant propagation.
id(I) -> I.