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vrp?
- From: Richard Henderson <rth at redhat dot com>
- To: Jeff Law <law at redhat dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Tue, 11 Feb 2003 22:58:55 -0800
- Subject: vrp?
Any idea what the state of the last value-range propagation patch is?
I've been looking at killing the cse-follow-jumps nonsense from cse.c,
and one case we're missing by removing it is
if (x == 0)
foo ();
else if (x == 0)
bar ();
The current cse code marks (x != 0) true on the else branch of the
first if. But our current gcse code has no way to make (x = NOT(0))
available on an edge.
I wouldn't think we'd need too terribly strong VRP to replace what
cse.c does now, but given how often this shows up within gcc source
itself I don't think I can kill what we have without a replacement.
Thoughts?
r~