libFIRM provides a graph-based intermediate representation (IR), which operates
exclusively in SSA-form, starting at IR construction until assembler code
emission.  It offers many analyses and optimizations, provides extensive
debugging support and includes a backend framework.

* analyses: dominance, loop tree, execution frequency, control dependencies,
  call graph, rapid type, def-use, alias analysis, class hierarchy analysis
* optimizations: dead code elimination (happens implicitly), constant folding,
  local common subexpression elimination, arithmetic identities (happens on the
  fly), unreachable code elimination, global common subexpression elimination,
  code placement, strength reduction, scalar replacement, if-conversion,
  load/store optimization, control flow optimizations, reassociation, partial
  condition evaluation, tail recursion elimination, inlining, procedure cloning
* enhanced debugging support: extensive checkers, breakpoints on node creation,
  entity creation, graph dumping
* lowering of intrinsics, double word arithmetics, bitfields
* generic backend features:
  * novel SSA based register allocator
  * several SSA copy coalescing and spilling algorithms
  * algorithms for instruction and basic block scheduling
* working ia32 backend, unfinished backends for ARM, MIPS, PPC32
* handwritten recursive descent C90/C99 frontend available (lang/cparser)

WWW: http://libfirm.org/