llvm-diff compares the structure of two LLVM modules, primarily focusing on differences in function
definitions. Insignificant differences, such as changes in the ordering of globals or in the names of
local values, are ignored.
An input module will be interpreted as an assembly file if its name ends in ‘.ll’; otherwise it will be
read in as a bitcode file.
If a list of global names is given, just the values with those names are compared; otherwise, all global
values are compared, and diagnostics are produced for globals which only appear in one module or the
other.
llvm-diff compares two functions by comparing their basic blocks, beginning with the entry blocks. If
the terminators seem to match, then the corresponding successors are compared; otherwise they are
ignored. This algorithm is very sensitive to changes in control flow, which tend to stop any downstream
changes from being detected.
llvm-diff is intended as a debugging tool for writers of LLVM passes and frontends. It does not have a
stable output format.