Update some comments noticed in a recent checkin
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51644 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/IA64/IA64ISelLowering.cpp b/lib/Target/IA64/IA64ISelLowering.cpp
index dbf205d..5d29200 100644
--- a/lib/Target/IA64/IA64ISelLowering.cpp
+++ b/lib/Target/IA64/IA64ISelLowering.cpp
@@ -91,12 +91,17 @@
setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand);
setOperationAction(ISD::LABEL, MVT::Other, Expand);
- //IA64 has these, but they are not implemented
- setOperationAction(ISD::CTTZ , MVT::i64 , Expand);
+ // IA64 has ctlz in the form of the 'fnorm' instruction. The Legalizer
+ // expansion for ctlz/cttz in terms of ctpop is much larger, but lower
+ // latency.
+ // FIXME: Custom lower CTLZ when compiling for size?
setOperationAction(ISD::CTLZ , MVT::i64 , Expand);
+ setOperationAction(ISD::CTTZ , MVT::i64 , Expand);
setOperationAction(ISD::ROTL , MVT::i64 , Expand);
setOperationAction(ISD::ROTR , MVT::i64 , Expand);
- setOperationAction(ISD::BSWAP, MVT::i64 , Expand); // mux @rev
+
+ // FIXME: IA64 has this, but is not implemented. should be mux @rev
+ setOperationAction(ISD::BSWAP, MVT::i64 , Expand);
// VASTART needs to be custom lowered to use the VarArgsFrameIndex
setOperationAction(ISD::VAARG , MVT::Other, Custom);