[LegalizeVectorOps] After custom legalizing an extending load or a truncating store, make sure the custom code is also legal.

For example, on X86 we emit a sign_extend_vector_inreg from LowerLoad and without sse4.1 this node will need further legalization. Previously this sign_extend_vector_inreg was being custom lowered during DAG legalization instead of vector op legalization.

Unfortunately, this doesn't seem to matter for the output of any existing lit tests.

llvm-svn: 347094

1 files changed, 10 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
index 17f05c3ba97..b4664f49201 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
@@ -244,7 +244,11 @@ SDValue VectorLegalizer::LegalizeOp(SDValue Op) {
         if (SDValue Lowered = TLI.LowerOperation(Result, DAG)) {
           assert(Lowered->getNumValues() == Op->getNumValues() &&
                  "Unexpected number of results");
-          Changed = Lowered != Result;
+          if (Lowered != Result) {
+            // Make sure the new code is also legal.
+            Lowered = LegalizeOp(Lowered);
+            Changed = true;
+          }
           return TranslateLegalizeResults(Op, Lowered);
         }
         LLVM_FALLTHROUGH;
@@ -266,7 +270,11 @@ SDValue VectorLegalizer::LegalizeOp(SDValue Op) {
         return TranslateLegalizeResults(Op, Result);
       case TargetLowering::Custom: {
         SDValue Lowered = TLI.LowerOperation(Result, DAG);
-        Changed = Lowered != Result;
+        if (Lowered != Result) {
+          // Make sure the new code is also legal.
+          Lowered = LegalizeOp(Lowered);
+          Changed = true;
+        }
         return TranslateLegalizeResults(Op, Lowered);
       }
       case TargetLowering::Expand: