Stuart Henderson <[email protected]> wrote: > On 2022/01/24 22:17, Jonathan Matthew wrote: > > The proposed update to lang/node makes this irrelevant, but I thought I'd > > send > > it anyway since it may come up elsewhere too. > > > > I noticed that on one system, 'npm install less' would abort, logging > > 'node: backwards memcpy', but on another it worked fine. Eventually I > > figured out this was because the working one had packages built with llvm > > 11, > > the other with llvm 13 packages, and llvm 13's memcpy optimiser was turning > > a series of small memcpys in node's bundled zlib into one larger one, > > without > > identifying that the src and dest of the larger memcpy could overlap. > > > > Compiling the bundled zlib with -fno-builtin-memcpy prevents it from doing > > that, which fixes npm. > > If we can't trust the compiler's builtin memcpy to do the right thing then > it probably needs disabling completely...
Right. We cannot conclude this is only in one specific piece of software. Has anyone reached opened a bug report with clang?
