"Vastly" eh? I seem to recall that LLVM ThinLTO has slight regressions compared to GCC LTO on specCPU but on Google's own applications the superior whole-program devirtualization offered only with ThinLTO is a net win.
replyI'll adjust my phrasing.
replyAs a user, building with thin-lto vs full-lto generally produces pretty similar performance in no small part because a huge amount of effort has gone into making the summaries as effective as possible for key performance needs.
As a compiler developer, especially when developing static analysis warnings rather than optimization passes, the number of cases where I've run into "this would be viable if we had full-lto" has been pretty high.
In practice the default ABI on linux x86-64 is still limiting you to binaries that are 4G or thereabout.
replyNot exactly a problem for LTO since any reasonable build machine will have 128GB of ram.
Yeah, I would have liked to see the paper specify whether the LTO they tried is fat LTO or ThinLTO.
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