Convert

    // fold (sub c1, c2) -> c1-c2

from a no-op into an actual transformation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55886 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 2d400bdfb2556064642a6e03c81b470474ce4751..4e4984789bcca92270a0d1fdee1950999b5ef4ea 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1111,7 +1111,7 @@ SDValue DAGCombiner::visitSUB(SDNode *N) {
     return DAG.getConstant(0, N->getValueType(0));
   // fold (sub c1, c2) -> c1-c2
   if (N0C && N1C)
-    return DAG.getNode(ISD::SUB, VT, N0, N1);
+    return DAG.getConstant(N0C->getAPIntValue() - N1C->getAPIntValue(), VT);
   // fold (sub x, c) -> (add x, -c)
   if (N1C)
     return DAG.getNode(ISD::ADD, VT, N0,