Dan Zimmerman via llvm-dev
2017-Dec-14 04:18 UTC
[llvm-dev] Interaction of --disable-llvm-passes and -O0
Pardon if this isn't the right forum for this question, but is there a reason that when both `--disable-llvm-passes` and `-O0` are passed to cc1 llvm optimization passes still appear to occur? For the past hour or so I was trying to figure out how to get a proper test for https://reviews.llvm.org/D41050 <https://reviews.llvm.org/D41050> out - as soon as I changed -O0 to -O3 (as suggested in this post: http://lists.llvm.org/pipermail/llvm-dev/2017-April/111989.html <http://lists.llvm.org/pipermail/llvm-dev/2017-April/111989.html>) the optimization passes didn't occur. Is this known/defined behavior? If so, is there documentation as to why it behaves that way? Dan -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20171213/a3529f9a/attachment.html>
David Blaikie via llvm-dev
2017-Dec-15 18:28 UTC
[llvm-dev] Interaction of --disable-llvm-passes and -O0
do you have a specific (reduced, ideally) example of -O0 --disable-llvm-passes still running passes? I'd certainly expect -O0 without --disable-llvm-passes to run passes (things like the AlwaysInliner, since respecting __attribute__((always_inline)) is necessary for program correctness, even at -O0), but would be surprised if disabling llvm passes didn't do what it says. On Fri, Dec 15, 2017 at 12:01 AM Dan Zimmerman via llvm-dev < llvm-dev at lists.llvm.org> wrote:> Pardon if this isn't the right forum for this question, but is there a > reason that when both `--disable-llvm-passes` and `-O0` are passed to cc1 > llvm optimization passes still appear to occur? For the past hour or so I > was trying to figure out how to get a proper test for > https://reviews.llvm.org/D41050 out - as soon as I changed -O0 to -O3 (as > suggested in this post: > http://lists.llvm.org/pipermail/llvm-dev/2017-April/111989.html) the > optimization passes didn't occur. Is this known/defined behavior? If so, is > there documentation as to why it behaves that way? > > Dan > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20171215/9af36922/attachment-0001.html>