| Summary: | media-libs/libdv-1.0.0-r4: undefined behavior with aggressive loop optimizations | ||
|---|---|---|---|
| Product: | Gentoo Linux | Reporter: | Jocelyn Mayer <l_indien> |
| Component: | Current packages | Assignee: | Gentoo Media-video project <media-video> |
| Status: | UNCONFIRMED --- | ||
| Severity: | normal | CC: | esigra, l_indien |
| Priority: | Normal | ||
| Version: | unspecified | ||
| Hardware: | AMD64 | ||
| OS: | Linux | ||
| See Also: | https://bugs.gentoo.org/show_bug.cgi?id=877711 | ||
| Whiteboard: | |||
| Package list: | Runtime testing required: | --- | |
| Bug Depends on: | |||
| Bug Blocks: | 915000 | ||
| Attachments: |
output from emerge --info =media-libs/libdv-1.0.0-r4
Log file for failing merge |
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Created attachment 824819 [details]
output from emerge --info =media-libs/libdv-1.0.0-r4
Created attachment 824821 [details]
Log file for failing merge
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While building libdv using gcc (clang untested) with -faggressive-loop-optimizations CFLAG set, I get this kind of message: iteration 11 invokes undefined behavior in libdv/encode.c Then, forcing adding -fno-aggressive-loop-optimizations and -fno--unsafe-loop-optimizations too all flags (for safety) solves the issue. Reproducible: Always Steps to Reproduce: 1. Put -faggressive-loop-optimizations -Wno-aggressive-loop-optimizations in compilation flags 2. Emerge libdv 3. See the output Actual Results: I got the 'undefined behavior' warning message Expected Results: It seems better not to have undefined behavior. The way I did is create a file in /etc/portage/env with the following and use it for libdv adding a reference in /etc/portage/package.env ADD_FLAGS="-fno-aggressive-loop-optimizations -fno-unsafe-loop-optimizations" CFLAGS="${CFLAGS} ${ADD_FLAGS} " CXXFLAGS="${CXXFLAGS} ${ADD_FLAGS}" FCFLAGS="${FCFLAGS} ${ADD_FLAGS}" FFLAGS="${FFLAGS} ${ADD_FLAGS}" LDFLAGS="${LDFLAGS} ${ADD_FLAGS}"