diff options
Diffstat (limited to 'lib/compiler/src')
| -rw-r--r-- | lib/compiler/src/beam_utils.erl | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl index 1b2a2827cb..bd1423cb40 100644 --- a/lib/compiler/src/beam_utils.erl +++ b/lib/compiler/src/beam_utils.erl @@ -318,6 +318,10 @@ check_liveness(R, [{block,Blk}|Is], St0) -> case check_liveness_block(R, Blk, St0) of {transparent,St1} -> check_liveness(R, Is, St1); + {alloc_used,St1} -> + %% Used by an allocating instruction, but value not referenced. + %% Must check the rest of the instructions. + not_used(check_liveness(R, Is, St1)); {Other,_}=Res when is_atom(Other) -> Res end; @@ -588,7 +592,7 @@ check_liveness_ret(R, R, St) -> {used,St}; check_liveness_ret(_, _, St) -> {killed,St}. %% check_liveness_block(Reg, [Instruction], State) -> -%% {killed | not_used | used | transparent,State'} +%% {killed | not_used | used | alloc_used | transparent,State'} %% Finds out how Reg is used in the instruction sequence inside a block. %% Returns one of: %% killed - Reg is assigned a new value or killed by an @@ -596,6 +600,7 @@ check_liveness_ret(_, _, St) -> {killed,St}. %% not_used - The value is not used, but the register is referenced %% e.g. by an allocation instruction %% transparent - Reg is neither used nor killed +%% alloc_used - Used only in an allocate instruction %% used - Reg is explicitly used by an instruction %% %% '%live' annotations are not allowed. @@ -609,7 +614,7 @@ check_liveness_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], St0) -> true -> case check_liveness_block_1(R, Ss, Ds, Op, Is, St0) of {killed,St} -> {not_used,St}; - {transparent,St} -> {not_used,St}; + {transparent,St} -> {alloc_used,St}; {_,_}=Res -> Res end end; |