Fix pattern sort in DAGISelEmitter.cpp

The old code skipped one of the sorting criteria if either pattern had
no types.  This could lead to cycles of the form X < Y, Y < Z, Z < X.

llvm-svn: 191735

1 files changed, 7 insertions, 9 deletions

diff --git a/llvm/utils/TableGen/DAGISelEmitter.cpp b/llvm/utils/TableGen/DAGISelEmitter.cpp
index b47dd71e88e..a76ea32de3e 100644
--- a/llvm/utils/TableGen/DAGISelEmitter.cpp
+++ b/llvm/utils/TableGen/DAGISelEmitter.cpp
@@ -81,15 +81,13 @@ struct PatternSortingPredicate {
     const TreePatternNode *LHSSrc = LHS->getSrcPattern();
     const TreePatternNode *RHSSrc = RHS->getSrcPattern();
 
-    if (LHSSrc->getNumTypes() != 0 && RHSSrc->getNumTypes() != 0 &&
-        LHSSrc->getType(0) != RHSSrc->getType(0)) {
-      MVT::SimpleValueType V1 = LHSSrc->getType(0), V2 = RHSSrc->getType(0);
-      if (MVT(V1).isVector() != MVT(V2).isVector())
-        return MVT(V2).isVector();
-
-      if (MVT(V1).isFloatingPoint() != MVT(V2).isFloatingPoint())
-        return MVT(V2).isFloatingPoint();
-    }
+    MVT LHSVT = (LHSSrc->getNumTypes() != 0 ? LHSSrc->getType(0) : MVT::Other);
+    MVT RHSVT = (RHSSrc->getNumTypes() != 0 ? RHSSrc->getType(0) : MVT::Other);
+    if (LHSVT.isVector() != RHSVT.isVector())
+      return RHSVT.isVector();
+
+    if (LHSVT.isFloatingPoint() != RHSVT.isFloatingPoint())
+      return RHSVT.isFloatingPoint();
 
     // Otherwise, if the patterns might both match, sort based on complexity,
     // which means that we prefer to match patterns that cover more nodes in the