[AVR] Expand 16-bit rotations during the legalization stage
In r356860, the legalization logic for BSWAP was modified to ISD::ROTL,
rather than the old ISD::{SHL, SRL, OR} nodes.
This works fine on AVR for 8-bit rotations, but 16-bit rotations are
currently unimplemented - they always trigger an assertion error in the
AVRExpandPseudoInsts pass ("RORW unimplemented").
This patch instructions the legalizer to expand 16-bit rotations into
the previous SHL, SRL, OR pattern it did previously.
This fixes the 'issue-cannot-select-bswap.ll' test. Interestingly, this
test failure seems flaky - it passes successfully on the avr-build-01
buildbot, but fails locally on my Arch Linux install.
llvm-svn: 362773
diff --git a/llvm/lib/Target/AVR/AVRISelLowering.cpp b/llvm/lib/Target/AVR/AVRISelLowering.cpp
index 3103c20..f6e1ba8 100644
--- a/llvm/lib/Target/AVR/AVRISelLowering.cpp
+++ b/llvm/lib/Target/AVR/AVRISelLowering.cpp
@@ -89,9 +89,9 @@
setOperationAction(ISD::SRL_PARTS, MVT::i16, Expand);
setOperationAction(ISD::ROTL, MVT::i8, Custom);
- setOperationAction(ISD::ROTL, MVT::i16, Custom);
+ setOperationAction(ISD::ROTL, MVT::i16, Expand);
setOperationAction(ISD::ROTR, MVT::i8, Custom);
- setOperationAction(ISD::ROTR, MVT::i16, Custom);
+ setOperationAction(ISD::ROTR, MVT::i16, Expand);
setOperationAction(ISD::BR_CC, MVT::i8, Custom);
setOperationAction(ISD::BR_CC, MVT::i16, Custom);