Fix a tblgen problem handling variable_ops in tblgen instruction

definitions. This adds a new construct, "discard", for indicating
that a named node in the input matching pattern is to be discarded,
instead of corresponding to a node in the output pattern. This
allows tblgen to know where the arguments for the varaible_ops are
supposed to begin.

This fixes "rdar://5791600", whatever that is ;-).

llvm-svn: 51699

1 files changed, 2 insertions, 0 deletions

diff --git a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
index 8c46b35fa19..006c067e8fd 100644
--- a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -916,6 +916,8 @@ bool TreePatternNode::ApplyTypeConstraints(TreePattern &TP, bool NotRegisters) {
         MadeChange |= Child->UpdateNodeType(MVT::iPTR, TP);
       } else if (OperandNode->getName() == "unknown") {
         MadeChange |= Child->UpdateNodeType(MVT::isUnknown, TP);
+      } else if (OperandNode->getName() == "discard") {
+        MadeChange |= Child->UpdateNodeType(MVT::isUnknown, TP);
       } else {
         assert(0 && "Unknown operand type!");
         abort();