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Re: Ada bootstrap failure due to new DCE bug
- From: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)
- To: rth at redhat dot com
- Cc: gcc at gcc dot gnu dot org
- Date: Fri, 6 Aug 04 09:29:54 EDT
- Subject: Re: Ada bootstrap failure due to new DCE bug
PS: The test case doesn't fail in C because the C front end decomposes
&arr[n] to pointer arithmetic, and that formation somehow does the
right thing in tree-ssa-alias.c. Not sure what the difference is,
exactly.
I'm not sure it has anything to do with decomposition vs. not decomposing
the reference. I tried to make a smaller test case for this in Ada and
failed because a memory tag wasn't used. The difficulty in reproducing
it in C may have been party due to that.
I've had a patch pending for ages to get C and C++ to not decompose
array_refs so early, but it doesn't work 100%. This may be the reason.
Indeed.
Thanks for looking into this so quickly and sorry that I was off email
yesterday.
BTW, I found a major bug on Tuesday in the way elaboration was done with in
the Ada front-end C code (gigi) that fixed a bunch of ACATS tests, so we're
down to about 37 failures, some of which may be specific to x86-64.
I think there's still a loop problem pending, since I have it loop
optimization off in my tree, but we're getting very close to being able to
consider Ada "working" again.