[PATCH] D22898: AMDGPU: Fix ffloor for SI

[Nicolai Hähnle via llvm-commits]

nhaehnle added a subscriber: nhaehnle.
nhaehnle added a comment.

Is the MIN needed for correctness at all? Looking at the workaround docs, I see the explanation that "[FRACT] is outputting 1.0 for very small negative inputs). Sounds to me like v_fract is correctly in the range [0, 1.0), except for those very small negative inputs, where it returns 1.0 (which happens to be correct for the ffloor lowering).


================
Comment at: lib/Target/AMDGPU/SIInstructions.td:3542
@@ -3541,3 +3541,3 @@
              SRCMODS.NONE,
-             (V_MOV_B64_PSEUDO 0x3fefffffffffffff),
+             CONST.FP64_ONE,
              DSTCLAMP.NONE, DSTOMOD.NONE),
----------------
Please also change the comment above.


https://reviews.llvm.org/D22898