[ARM][MVE] Add support for incrementing gathers

Enables the MVEGatherScatterLowering pass to build
pre-incrementing gathers. Incrementing writeback gathers
are built when it is possible to replace the loop increment
instruction.

Differential Revision: https://reviews.llvm.org/D76786

llvm/lib/Target/ARM/ARMBaseInstrInfo.h

@@ -21,6 +21,8 @@
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineOperand.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/IntrinsicsARM.h"
 #include <array>
 #include <cstdint>
 
@@ -831,6 +833,27 @@ inline bool isLegalAddressImm(unsigned Opcode, int Imm,
   }
 }
 
+// Return true if the given intrinsic is a gather or scatter
+inline bool isGatherScatter(IntrinsicInst *IntInst) {
+  if (IntInst == nullptr)
+    return false;
+  unsigned IntrinsicID = IntInst->getIntrinsicID();
+  return (IntrinsicID == Intrinsic::masked_gather ||
+          IntrinsicID == Intrinsic::arm_mve_vldr_gather_base ||
+          IntrinsicID == Intrinsic::arm_mve_vldr_gather_base_predicated ||
+          IntrinsicID == Intrinsic::arm_mve_vldr_gather_base_wb ||
+          IntrinsicID == Intrinsic::arm_mve_vldr_gather_base_wb_predicated ||
+          IntrinsicID == Intrinsic::arm_mve_vldr_gather_offset ||
+          IntrinsicID == Intrinsic::arm_mve_vldr_gather_offset_predicated ||
+          IntrinsicID == Intrinsic::masked_scatter ||
+          IntrinsicID == Intrinsic::arm_mve_vstr_scatter_base ||
+          IntrinsicID == Intrinsic::arm_mve_vstr_scatter_base_predicated ||
+          IntrinsicID == Intrinsic::arm_mve_vstr_scatter_base_wb ||
+          IntrinsicID == Intrinsic::arm_mve_vstr_scatter_base_wb_predicated ||
+          IntrinsicID == Intrinsic::arm_mve_vstr_scatter_offset ||
+          IntrinsicID == Intrinsic::arm_mve_vstr_scatter_offset_predicated);
+}
+
 } // end namespace llvm
 
 #endif // LLVM_LIB_TARGET_ARM_ARMBASEINSTRINFO_H