[SelectionDAG] Add some comments to ISDOpcodes.h about the operands of MLOAD, MSTORE, MGATHER, MSCATTER. NFC

llvm-svn: 340898

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/include/llvm/CodeGen/ISDOpcodes.h b/llvm/include/llvm/CodeGen/ISDOpcodes.h
index 80bd796d537..842f27f19e1 100644
--- a/llvm/include/llvm/CodeGen/ISDOpcodes.h
+++ b/llvm/include/llvm/CodeGen/ISDOpcodes.h
@@ -786,11 +786,20 @@ namespace ISD {
     // Masked load and store - consecutive vector load and store operations
     // with additional mask operand that prevents memory accesses to the
     // masked-off lanes.
+    //
+    // Val, OutChain = MLOAD(BasePtr, Mask, PassThru)
+    // OutChain = MSTORE(Value, BasePtr, Mask)
     MLOAD, MSTORE,
 
     // Masked gather and scatter - load and store operations for a vector of
     // random addresses with additional mask operand that prevents memory
     // accesses to the masked-off lanes.
+    //
+    // Val, OutChain = GATHER(InChain, PassThru, Mask, BasePtr, Index, Scale)
+    // OutChain = SCATTER(InChain, Value, Mask, BasePtr, Index, Scale)
+    //
+    // The Index operand can have more vector elements than the other operands
+    // due to type legalization. The extra elements are ignored.
     MGATHER, MSCATTER,
 
     /// This corresponds to the llvm.lifetime.* intrinsics. The first operand