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Re: [tree-ssa]: The dangers of keeping constants in phi nodes
- From: Daniel Berlin <dberlin at dberlin dot org>
- To: Daniel Berlin <dberlin at dberlin dot org>
- Cc: Diego Novillo <dnovillo at redhat dot com>,gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Sun, 4 Jan 2004 23:27:43 -0500
- Subject: Re: [tree-ssa]: The dangers of keeping constants in phi nodes
- References: <AA0FDFE6-3F2C-11D8-9460-000A95DA505C@dberlin.org>
On Jan 4, 2004, at 10:10 PM, Daniel Berlin wrote:
If you rewrite a var which had a constant propagated into a phi node,
it loses the phi node value (IE it never unpropagates it temporarily,
or remembers it was there), and thus, you lose the initialization.
There is no warning that this occurred, and unless you noticed it
otherwise, it's not easy to catch.
This is clearly a bug.
I never noticed that we can only rename *new* variables according to
the API, so it's technically not a bug.