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-rw-r--r--lib/compiler/src/beam_bool.erl12
-rw-r--r--lib/compiler/test/andor_SUITE.erl30
2 files changed, 37 insertions, 5 deletions
diff --git a/lib/compiler/src/beam_bool.erl b/lib/compiler/src/beam_bool.erl
index ffe5cdb501..dcc6ad4c7c 100644
--- a/lib/compiler/src/beam_bool.erl
+++ b/lib/compiler/src/beam_bool.erl
@@ -173,7 +173,7 @@ bopt_block(Reg, Fail, OldIs, [{block,Bl0}|Acc0], St0) ->
%% whether the optimized code is guaranteed to work in the same
%% way as the original code.
%%
-%% Throws an exception if the optmization is not safe.
+%% Throw an exception if the optimization is not safe.
%%
ensure_opt_safe(Bl, NewCode, OldIs, Fail, PreceedingCode, St) ->
%% Here are the conditions that must be true for the
@@ -190,10 +190,10 @@ ensure_opt_safe(Bl, NewCode, OldIs, Fail, PreceedingCode, St) ->
%% by the code that follows.
%%
%% 3. Any register that is assigned a value in the optimized
- %% code must be UNUSED or KILLED in the following code.
- %% (Possible future improvement: Registers that are known
- %% to be assigned the SAME value in the original and optimized
- %% code don't need to be unused in the following code.)
+ %% code must be UNUSED or KILLED in the following code
+ %% (because the register might be assigned the wrong value,
+ %% and even if the value is right it might no longer be
+ %% assigned on *all* paths leading to its use).
InitInPreceeding = initialized_regs(PreceedingCode),
@@ -310,6 +310,8 @@ dst_regs([{set,[D],_,{bif,_,{f,_}}}|Is], Acc) ->
dst_regs(Is, [D|Acc]);
dst_regs([{set,[D],_,{alloc,_,{gc_bif,_,{f,_}}}}|Is], Acc) ->
dst_regs(Is, [D|Acc]);
+dst_regs([{set,[D],_,move}|Is], Acc) ->
+ dst_regs(Is, [D|Acc]);
dst_regs([_|Is], Acc) ->
dst_regs(Is, Acc);
dst_regs([], Acc) -> ordsets:from_list(Acc).
diff --git a/lib/compiler/test/andor_SUITE.erl b/lib/compiler/test/andor_SUITE.erl
index 6e3ac4d4f4..a460d54239 100644
--- a/lib/compiler/test/andor_SUITE.erl
+++ b/lib/compiler/test/andor_SUITE.erl
@@ -390,6 +390,15 @@ before_and_inside_if(Config) when is_list(Config) ->
?line yes = before_and_inside_if([], [], x),
?line yes = before_and_inside_if([], [b], delete),
?line yes = before_and_inside_if([], [b], x),
+
+ ?line {ch1,ch2} = before_and_inside_if_2([a], [b], blah),
+ ?line {ch1,ch2} = before_and_inside_if_2([a], [b], xx),
+ ?line {ch1,ch2} = before_and_inside_if_2([a], [], blah),
+ ?line {ch1,ch2} = before_and_inside_if_2([a], [], xx),
+ ?line {no,no} = before_and_inside_if_2([], [b], blah),
+ ?line {no,no} = before_and_inside_if_2([], [b], xx),
+ ?line {ch1,no} = before_and_inside_if_2([], [], blah),
+ ?line {no,ch2} = before_and_inside_if_2([], [], xx),
ok.
%% Thanks to Simon Cornish and Kostis Sagonas.
@@ -408,6 +417,27 @@ before_and_inside_if(XDo1, XDo2, Do3) ->
yes
end.
+%% Thanks to Simon Cornish.
+%% Used to generate code that would not set {y,0} on
+%% all paths before its use (and therefore fail
+%% validation by the beam_validator).
+before_and_inside_if_2(XDo1, XDo2, Do3) ->
+ Do1 = (XDo1 =/= []),
+ Do2 = (XDo2 =/= []),
+ CH1 = if Do1 == true;
+ Do1 == false,Do2==false,Do3 == blah ->
+ ch1;
+ true ->
+ no
+ end,
+ CH2 = if Do1 == true;
+ Do1 == false,Do2==false,Do3 == xx ->
+ ch2;
+ true ->
+ no
+ end,
+ {CH1,CH2}.
+
%% Utilities.
check(V1, V0) ->