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Re: block merging
- To: law at cygnus dot com
- Subject: Re: block merging
- From: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)
- Date: Mon, 20 Sep 99 17:33:06 EDT
- Cc: gcc-patches at gcc dot gnu dot org
I've just run into a case where the improved block merging code can create
jump X
NOTE
BARRIER
X
When we delete the jump X, we do not delete the BARRIER because it
does not immediately follow the jump. Opps.
I'm pondering the best fix.
Although it's a major conceptual change, it may well be that the right
approach is to weaken the test and have a BARRIER get deleted even though
it's separated by one or more NOTEs from the JUMP_INSN (or CALL_INSN).
I think this is more robust under the principle of "be liberal and what you
expect and conservative in what you generate".