1LLVM-DIFF(1)                  LLVM Command Guide                  LLVM-DIFF(1)
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NAME

6       llvm-diff - LLVM structural 'diff'
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SYNOPSIS

9       llvm-diff [options] module 1 module 2 [global name ...]
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DESCRIPTION

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

35       If llvm-diff finds no differences between the modules, it will exit
36       with 0 and produce no output.  Otherwise it will exit with a non-zero
37       value.
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BUGS

40       Many important differences, like changes in linkage or function
41       attributes, are not diagnosed.
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43       Changes in memory behavior (for example, coalescing loads) can cause
44       massive detected differences in blocks.
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AUTHORS

47       Maintained by the LLVM Team (<http://llvm.org>).
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51CVS                               2010-09-07                      LLVM-DIFF(1)