[PATCH] D39040: AMDGPU: Fix creating invalid copy when adjusting dmask

[Marek Olšák via Phabricator via llvm-commits]

mareko added a comment.

Each bit of dmask determines whether that component is enabled.  Image opcodes return 4 components if dmask == 0xf. If dmask == 0x2, image opcodes only return the 2nd component in <1 x float>. If dmask = 0x5, image opcodes return the 1st and 3rd component in <2 x float>. If dmask = 0xa, image opcodes return the 2nd and 4th component in <2 x float>.
Gather4 opcodes are an exception and always return 4 components.


https://reviews.llvm.org/D39040