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| author | Kaz Kylheku <kaz@kylheku.com> | 2021-04-22 06:42:44 -0700 |
|---|---|---|
| committer | Kaz Kylheku <kaz@kylheku.com> | 2021-04-22 06:42:44 -0700 |
| commit | 43303f6ce29bf502644c27115b0d9b680142f989 (patch) | |
| tree | ef2b782e30b06703415ef061d39c11923d97f280 | |
| parent | 2480aea51560801f436823c53dc408a7333f683b (diff) | |
| download | txr-43303f6ce29bf502644c27115b0d9b680142f989.tar.gz txr-43303f6ce29bf502644c27115b0d9b680142f989.tar.bz2 txr-43303f6ce29bf502644c27115b0d9b680142f989.zip | |
compiler: bug: graph issue in dead code elimination.
* share/txr/stdlib/optimize.tl (basic-blocks join-block): When
we merge a block N with its physical predecessor P, we must
iterate over the jump targets of N, and update their reverse
list to point to P instead of N. A full call to link-graph
would fix it also, but we don't call link-graph anywhere in
the optimization pipeline after this point. The reverse
links are relied on to be correct elsewhere, such
merge-jump-tunks, which needs to walk the blocks which jump
to a removed duplicate block, to retarget them to go to
another copy of that block.
| -rw-r--r-- | share/txr/stdlib/optimize.tl | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/share/txr/stdlib/optimize.tl b/share/txr/stdlib/optimize.tl index 83abaa1e..b011c568 100644 --- a/share/txr/stdlib/optimize.tl +++ b/share/txr/stdlib/optimize.tl @@ -107,7 +107,10 @@ (set bl.next nxbl.next) (set bl.links nxbl.links) (set bb.list (remq nxbl bb.list)) - (del [bb.hash nxbl.label])))) + (del [bb.hash nxbl.label]) + (each ((nx bl.links)) + (upd nx.rlinks (remq nxbl)) + (pushnew bl nx.rlinks))))) (defmacro rewrite-case (sym list . cases) ^(rewrite (lambda (,sym) |