While building clang-8.0.0 or firefox-66.0.3 on a gentoo system (x86_64) gcc 9 release candidate runs out of memory with -O2 -ggdb. Gcc 8.3.0 succeeds without issues. For clang there are about 5-6 compilations where the memory usage seems to grow without bound (I have 128Gb RAM + 128Gb swap and at least two of them were observed to reach 80+Gb each before getting killed).
For 8.3.0 nothing seems to reach more than single-digit Gb. Without the -ggdb switch gcc 9 also builds fine without excessive memory usage. Files running out of memory: lib/Parse/ParseDeclCXX.cpp lib/Parse/ParseTentative.cpp lib/StaticAnalyzer/Checkers/MallocSizeofChecker.cpp lib/Format/FormatTokenLexer.cpp lib/Format/TokenAnnotator.cpp The assembler output for all but the MallocSizeChecker.cpp was still 0 bytes when the compiler crashed, and it wasn't growing for that one. Experimenting with different -g and -gdwarf levels instead of passing in -ggdb, -g2 -gdwarf-4 crashes, -g2 -gdwarf-3 crashes, -g1 -gdwarf-4 crashes. Both gcc 8.3.0 and 9 were bootstrapped using profiledbootstrap + --with-build-config=bootstrap-lto at -O2. In addition my gcc 9 is currently built with some additional optimization options: ira-loop-pressure, live-range-shrinkage, tree-lrs. I'll try bootstrapping 9 with regular -O2 without pgo/lto and see if that is better. I realize this is a rather low-quality report :) but have little experience in trying to narrow this down esp with cmake being used in clang build, and throwing this out there in case someone else can take a quick look. PS I am not on the list, please include me explicitly on replies.
