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authorBjörn Gustavsson <[email protected]>2019-08-01 10:24:23 +0200
committerBjörn Gustavsson <[email protected]>2019-08-01 10:24:23 +0200
commitc7ac8d9bf26cbb04c2942e792f766a2ba6d8b07e (patch)
treeb0ddf6ca605ccc5e198d4f739716c09d31223022 /lib/compiler/src
parent1a8f8b199589b5a16b22489e6501f13fbc2e1b54 (diff)
parente553fbc8d6e55773172358f75c7e83ab38f0cb4c (diff)
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Merge branch 'bjorn/compiler/fix-unsafe-sharing/OTP-15963' into maint
* bjorn/compiler/fix-unsafe-sharing/OTP-15963: Fix unsafe code sharing
Diffstat (limited to 'lib/compiler/src')
-rw-r--r--lib/compiler/src/beam_ssa_share.erl8
1 files changed, 6 insertions, 2 deletions
diff --git a/lib/compiler/src/beam_ssa_share.erl b/lib/compiler/src/beam_ssa_share.erl
index 426efa2cc9..73983bd34a 100644
--- a/lib/compiler/src/beam_ssa_share.erl
+++ b/lib/compiler/src/beam_ssa_share.erl
@@ -303,8 +303,12 @@ canonical_is([#b_ret{arg=Arg}], VarMap, Acc0) ->
Acc0
end,
{{ret,canonical_arg(Arg, VarMap),Acc1},VarMap};
-canonical_is([#b_br{bool=#b_var{},fail=Fail}], VarMap, Acc) ->
- {{br,succ,Fail,Acc},VarMap};
+canonical_is([#b_br{bool=#b_var{}=Arg,fail=Fail}], VarMap, Acc) ->
+ %% A previous buggy version of this code omitted the canonicalized
+ %% argument in the return value. Unfortunately, that worked most
+ %% of the time, except when `br` terminator referenced a variable
+ %% defined in a previous block instead of in the same block.
+ {{br,canonical_arg(Arg, VarMap),succ,Fail,Acc},VarMap};
canonical_is([#b_br{succ=Succ}], VarMap, Acc) ->
{{br,Succ,Acc},VarMap};
canonical_is([], VarMap, Acc) ->