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| author | Bernhard Schommer <bernhardschommer@gmail.com> | 2023-02-13 11:59:41 +0100 |
|---|---|---|
| committer | Xavier Leroy <xavier.leroy@college-de-france.fr> | 2023-02-20 09:43:38 +0100 |
| commit | 9d06ed97f493f89ab41f1dc3962840eadacd3865 (patch) | |
| tree | 5d4c5df92b19de4400d0dae39b2e7a79a7c5bf42 /backend/Selection.v | |
| parent | 243c0f7ce4e8b6c22ddd930bd470ab74187e5256 (diff) | |
| download | compcert-9d06ed97f493f89ab41f1dc3962840eadacd3865.tar.gz compcert-9d06ed97f493f89ab41f1dc3962840eadacd3865.zip | |
Ignore self assign in if-conversion
A self assign `x = x` can be classified as a skip in `classify_stmt`.
This helps with the if-conversion of some code that the previous passes
generates, e.g. for nested C conditional expressions.
Closes: #466
Diffstat (limited to 'backend/Selection.v')
| -rw-r--r-- | backend/Selection.v | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/backend/Selection.v b/backend/Selection.v index ca1f1619..e4be867f 100644 --- a/backend/Selection.v +++ b/backend/Selection.v @@ -348,7 +348,11 @@ Inductive stmt_class : Type := Fixpoint classify_stmt (s: Cminor.stmt) : stmt_class := match s with | Cminor.Sskip => SCskip - | Cminor.Sassign id a => SCassign id a + | Cminor.Sassign id a => + match a with + | Cminor.Evar id2 => if ident_eq id id2 then SCskip else SCassign id a + | _ => SCassign id a + end | Cminor.Sbuiltin None (EF_debug _ _ _) _ => SCskip | Cminor.Sseq s1 s2 => match classify_stmt s1, classify_stmt s2 with |