-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 05/25/11 06:40, Bernd Schmidt wrote: > >> >> The code in question is literally 20 years old and predates running any >> real dead code elimination after reload. ISTM the right thing to do is >> stop using delete_dead_insn in this code and let the post-reload DCE >> pass do its job. That allows us to continue to record the block local >> equivalence. > > Sounds like the right thing to do. OK. (Can we eliminate the other caller?) I didn't look too hard at the other call; looking at it now, I think we can probably safely remove it and just delete the single insn which sets the eliminable register.
I can either add that to the existing patch or submit it as a follow-up. I've got no strong preference on this issue. > > I've looked at code generation; it appears unchanged on i686-linux, > which I think is the expected result. There are minor differences in > assembly output on mips64-linux. If you want to look at it, I'm > attaching a testcase - compile with "-O2 -fno-reorder-blocks". I'm a little surprised to hear there is a codegen difference, though I can envision a variety of ways that could happen. The undeleted insns might interfere with the post-reload optimizers which run before dce for example. I'll take a quick look. jeff -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJN3StDAAoJEBRtltQi2kC7kGAH/R7DzEkkQdaNj6xQjTXtqKs5 hv9mngz5lEovhaZvpdmRw8pc4mBcis1P4s9jgD3boj1aX3R8PQu+WsL6br5DzduA b+TtRDyVPazOSrc1mMLiCZr81rbSQfEzCWBWK1ZHLPA2oQNw8v211HtPoTxg1qsq kXyArAnd/bQBip9AJHEh1J3yOyFkV5eNDODZPIl8hvGhIyRlJz+R72v3eRwT+oCA 65mU1Zfqykul+BKtJG1uj13gtTsroxHjZYI/iCmVMYriDFWIyj7qLgNtNOxx9yTQ sFQbJqJX9cdXIgcAJoijzpT+bLubSeGUaWgjZgqG/AwU5vEXkOp8etBGeUZNg2Q= =bSzC -----END PGP SIGNATURE-----
