SIInsertWaitcnts inserts waitcnt instructions to resolve data
dependencies. The GFX10+ vscnt (VMEM store count) counter is never used
in this way. It is only used to resolve memory dependencies, and that is
handled by SIMemoryLegalizer. Hence there is no need to conservatively
wait for vscnt to be 0 on function entry and before returns.
Differential Revision: https://reviews.llvm.org/D153537
If a call to the llvm.fabs intrinsic has users in another reachable
BB, SelectionDAG will not apply the abs modifier to these users and
instead generate a v_and ..., 0x7fffffff instruction.
For fneg instructions, the issue is similar.
This patch implements `AMDGPUIselLowering::shouldSinkOperands`,
which allows CodegenPrepare to call `tryToSinkFreeOperands`.
Reviewed By: foad
Differential Revision: https://reviews.llvm.org/D150347
