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| author | Xavier Leroy <xavier.leroy@inria.fr> | 2014-05-16 14:37:22 +0000 |
|---|---|---|
| committer | Xavier Leroy <xavier.leroy@inria.fr> | 2014-05-16 14:37:22 +0000 |
| commit | 657ba73021599ec386f65d4e07ff2d7445d864f4 (patch) | |
| tree | 21485fe3f74709e2bedbc870b8cc1e71405c6534 /asmcomp/liveness.ml | |
| parent | 6d25df3c9bb2b5ea59463cd3832d4b06a02c6b68 (diff) | |
| download | ocaml-657ba73021599ec386f65d4e07ff2d7445d864f4.tar.gz | |
Liveness & Deadcode: fix i386-specific issue with move instructions accessing
the x87 FP stack, which must not be eliminated.
CSEgen: harden against the same x87-specific issue + against reuse of
values in fixed hardware registers that were destroyed by a prior
operation.
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14877 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Diffstat (limited to 'asmcomp/liveness.ml')
| -rw-r--r-- | asmcomp/liveness.ml | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/asmcomp/liveness.ml b/asmcomp/liveness.ml index c5b0c0a3a1..2ef322ef3e 100644 --- a/asmcomp/liveness.ml +++ b/asmcomp/liveness.ml @@ -41,7 +41,11 @@ let rec live i finally = Reg.set_of_array i.arg | Iop op -> let after = live i.next finally in - if Proc.op_is_pure op && Reg.disjoint_set_array after i.res then begin + if Proc.op_is_pure op (* no side effects *) + && Reg.disjoint_set_array after i.res (* results are not used after *) + && not (Proc.regs_are_volatile i.arg) (* no stack-like hard reg *) + && not (Proc.regs_are_volatile i.res) (* is involved *) + then begin (* This operation is dead code. Ignore its arguments. *) i.live <- after; after |