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Re: optimization/6822: GCC 3.1.1 - Internal compiler error in extract_insn, at recog.c:2132
- From: Glen Nakamura <glen at imodulo dot com>
- To: gcc-gnats at gcc dot gnu dot org, gcc-bugs at gcc dot gnu dot org
- Date: Tue, 28 May 2002 03:54:54 -1000
- Subject: Re: optimization/6822: GCC 3.1.1 - Internal compiler error in extract_insn, at recog.c:2132
I believe the following patch is the cause of this PR:
2002-05-15 Eric Botcazou <email@example.com>
* fold-const.c (fold) [LT_EXPR]: Move the transformation of a
comparison against the highest or lowest integer value before
the 'X >= CST to X > (CST - 1)' and 'X < CST to X <= (CST - 1)'
transformation and that of an unsigned comparison against 0
Previously, unsigned X < 128 would be converted to unsigned X <= 127 and
then optimized to signed X >= 0. After changing the order of the
transformations, the compiler only reduces the expression to X <= 127 ???
The result is the reported ICE. This could very well be a latent bug
in other parts of the compiler, but it seems the change results in missed
opportunities to simplify expressions. I'll post an alternative patch
in my next message...
- Glen Nakamura