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[Bug pch/14137] [pch] ICE in cgraph_finalize_compilation_unit, at cgraphunit.c:407
- From: "bangerth at dealii dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 30 Mar 2004 23:26:03 -0000
- Subject: [Bug pch/14137] [pch] ICE in cgraph_finalize_compilation_unit, at cgraphunit.c:407
- References: <20040213062200.14137.mattyt-bugzilla@tpg.com.au>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From bangerth at dealii dot org 2004-03-30 23:25 -------
In my view, if compilation time is a problem, then
a) the project is big,
b) we are talking about regular builds, not ones where someone
is playing with compiler options, and
b) very likely people are using a makefile to build things.
It seems very likely that within a Makefile, the number of different
combinations of flags is relatively small (say: 2, one for debug, one
for optimized builds), and in this case it is reasonable to ask them
that they generate one pch file per set of flags. After all, we support
this, by putting multiple pch files into one directory.
I consider simply requiring the user to use the exact same combination
of flags as an absolutely acceptable requirement and am not expecting
that we get many bug reports. On the other hand, if we get reports about
incorrect code generation due to problems with PCH, this is going to be
significantly worse. Please also keep in mind here that PCH bugs are us
bugmasters' worst nightmares, since they often come in huge chunks,
involve not only a single preprocessed file but a large collection of header
files, may involve different compilation flags for different parts of the
build, etc. PCH bugs have been very resistant to our efforts in the past,
and have most often been analysed by the people who know how PCH is
implemented, rather than by bugzilla people. I therefore very strongly
urge you to go the safe route and only allow mixing compilation flags for
PCH generation and PCH use if we are _absolutely_ (double-checked, verifiably)
sure that this is safe!
W.
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14137