R600: Print Export Swizzle
R600: Use DAG lowering pass to handle fcos/fsin

NOTE: This is a candidate for the stable branch.
R600: Fix wrong export reswizzling
R600: Fix a rare bug where swizzle optimization returns wrong values
R600: Do not predicated basic block with multiple alu clause

Test is not included as it is several 1000 lines long.
To test this functionnality, a test case must generate at least 2 ALU clauses,
where an ALU clause is ~110 instructions long.

NOTE: This is a candidate for the stable branch.