[GlobalISel] Add a G_FRINT opcode

[paquette]

Summary

Equivalent to SelectionDAG's frint node.

[paquette]

Remove change to AArch64RegisterBankInfo.cpp; I want that to come in with a later commit where it makes more sense.

[aemerson]

LGTM.

llvm/include/llvm/Support/TargetOpcodes.def

 HANDLE_TARGET_OPCODE(G_FSIN)
 
 /// Floating point square root.
 HANDLE_TARGET_OPCODE(G_FSQRT)
 
 /// Floating point floor.
 HANDLE_TARGET_OPCODE(G_FFLOOR)
 
+/// Floating point round to next integer.
+HANDLE_TARGET_OPCODE(G_FRINT)
+
 /// Generic AddressSpaceCast.
 HANDLE_TARGET_OPCODE(G_ADDRSPACE_CAST)
 
 /// Generic block address
 HANDLE_TARGET_OPCODE(G_BLOCK_ADDR)
 
 // TODO: Add more generic opcodes as we move along.
 
 /// Marker for the end of the generic opcode.
 /// This is used to check if an opcode is in the range of the
 /// generic opcodes.
 HANDLE_TARGET_OPCODE_MARKER(PRE_ISEL_GENERIC_OPCODE_END, G_BLOCK_ADDR)
 
 /// BUILTIN_OP_END - This must be the last enum value in this list.
 /// The target-specific post-isel opcode values start here.
 HANDLE_TARGET_OPCODE_MARKER(GENERIC_OP_END, PRE_ISEL_GENERIC_OPCODE_END)

llvm/include/llvm/Target/GenericOpcodes.td

 
 // Floating point floor of a value.
 def G_FFLOOR : GenericInstruction {
   let OutOperandList = (outs type0:$dst);
   let InOperandList = (ins type0:$src1);
   let hasSideEffects = 0;
 }
 
+// Floating point round to next integer.
+def G_FRINT : GenericInstruction {
+  let OutOperandList = (outs type0:$dst);
+  let InOperandList = (ins type0:$src1);
+  let hasSideEffects = 0;
+}
+
 //------------------------------------------------------------------------------
 // Opcodes for LLVM Intrinsics
 //------------------------------------------------------------------------------
 def G_INTRINSIC_TRUNC : GenericInstruction {
   let OutOperandList = (outs type0:$dst);
   let InOperandList = (ins type0:$src1);
   let hasSideEffects = 0;
 }

llvm/include/llvm/Target/GlobalISel/SelectionDAGCompat.td

 def : GINodeEquiv<G_EXTRACT_VECTOR_ELT, vector_extract>;
 def : GINodeEquiv<G_CONCAT_VECTORS, concat_vectors>;
 def : GINodeEquiv<G_FCEIL, fceil>;
 def : GINodeEquiv<G_FCOS, fcos>;
 def : GINodeEquiv<G_FSIN, fsin>;
 def : GINodeEquiv<G_FABS, fabs>;
 def : GINodeEquiv<G_FSQRT, fsqrt>;
 def : GINodeEquiv<G_FFLOOR, ffloor>;
+def : GINodeEquiv<G_FRINT, frint>;
 
 // Broadly speaking G_LOAD is equivalent to ISD::LOAD but there are some
 // complications that tablegen must take care of. For example, Predicates such
 // as isSignExtLoad require that this is not a perfect 1:1 mapping since a
 // sign-extending load is (G_SEXTLOAD x) in GlobalISel. Additionally,
 // G_LOAD handles both atomic and non-atomic loads where as SelectionDAG had
 // separate nodes for them. This GINodeEquiv maps the non-atomic loads to
 // G_LOAD with a non-atomic MachineMemOperand.

llvm/test/CodeGen/AArch64/GlobalISel/legalizer-info-validation.mir

 #
 # DEBUG-NEXT: G_FSIN (opcode {{[0-9]+}}): 1 type index
 # DEBUG: .. the first uncovered type index: 1, OK
 #
 # DEBUG-NEXT: G_FSQRT (opcode {{[0-9]+}}): 1 type index
 # DEBUG: .. type index coverage check SKIPPED: user-defined predicate detected
 #
 # DEBUG-NEXT: G_FFLOOR (opcode {{[0-9]+}}): 1 type index
+# DEBUG: .. type index coverage check SKIPPED: user-defined predicate detected
+#
+# DEBUG-NEXT: G_FRINT (opcode 146): 1 type index
 # DEBUG: .. type index coverage check SKIPPED: no rules defined
 
 # CHECK-NOT: ill-defined
 
 ---
 name: dummy
 body: |
   bb.0:
 ...