Commits on Nov 9, 2023

1. [BranchFolding] Remove dubious assert from operator< (#71639) …

   `MergePotentialElts::operator<` asserts that the two elements being
   compared are not equal. However, sorting functions are allowed to invoke
   the comparison function with equal arguments (though they usually don't
   for efficiency reasons).
   
   There is an existing special-case that disables the assert if
   _GLIBCXX_DEBUG is used, which may invoke the comparator with equal args
   to verify strict weak ordering. I believe libc++ also has strict weak
   ordering checks under some options nowadays.
   
   Recently, #71312 was reported, where a change to glibc's qsort_r
   implementation can also result in comparison between equal elements.
   From what I understood, this is an inefficiency that will be fixed on
   the glibc side as well, but I think at this point we should just remove
   this assertion.
   
   Fixes llvm/llvm-project#71312.
   
   (cherry picked from commit 74a76a288562c486f377121855ef7db0386e0e43)

   

   nikic authored and llvmbot committed Nov 9, 2023
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