Merging r200743:

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r200743 | michel.daenzer | 2014-02-03 23:12:38 -0800 (Mon, 03 Feb 2014) | 11 lines

R600/SI: Fix fneg for 0.0

V_ADD_F32 with source modifier does not produce -0.0 for this. Just
manipulate the sign bit directly instead.

Also add a pattern for (fneg (fabs ...)).

Fixes a bunch of bit encoding piglit tests with radeonsi.

Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
llvm-svn: 204643