SDAG: Handle scalarizing an extend of a <1 x iN> vector.

Just scalarize the element and rebuild a vector of the result type
from that.

rdar://13281568

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176614 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 40 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index 7de42ea..27b3cf2 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -530,6 +530,7 @@ private:
   // Vector Operand Scalarization: <1 x ty> -> ty.
   bool ScalarizeVectorOperand(SDNode *N, unsigned OpNo);
   SDValue ScalarizeVecOp_BITCAST(SDNode *N);
+  SDValue ScalarizeVecOp_EXTEND(SDNode *N);
   SDValue ScalarizeVecOp_CONCAT_VECTORS(SDNode *N);
   SDValue ScalarizeVecOp_EXTRACT_VECTOR_ELT(SDNode *N);
   SDValue ScalarizeVecOp_STORE(StoreSDNode *N, unsigned OpNo);
diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index 09a50d9..5ec8535 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -365,6 +365,11 @@ bool DAGTypeLegalizer::ScalarizeVectorOperand(SDNode *N, unsigned OpNo) {
     case ISD::BITCAST:
       Res = ScalarizeVecOp_BITCAST(N);
       break;
+    case ISD::ANY_EXTEND:
+    case ISD::ZERO_EXTEND:
+    case ISD::SIGN_EXTEND:
+      Res = ScalarizeVecOp_EXTEND(N);
+      break;
     case ISD::CONCAT_VECTORS:
       Res = ScalarizeVecOp_CONCAT_VECTORS(N);
       break;
@@ -400,6 +405,21 @@ SDValue DAGTypeLegalizer::ScalarizeVecOp_BITCAST(SDNode *N) {
                      N->getValueType(0), Elt);
 }
 
+/// ScalarizeVecOp_EXTEND - If the value to extend is a vector that needs
+/// to be scalarized, it must be <1 x ty>.  Extend the element instead.
+SDValue DAGTypeLegalizer::ScalarizeVecOp_EXTEND(SDNode *N) {
+  assert(N->getValueType(0).getVectorNumElements() == 1 &&
+         "Unexected vector type!");
+  SDValue Elt = GetScalarizedVector(N->getOperand(0));
+  SmallVector<SDValue, 1> Ops(1);
+  Ops[0] = DAG.getNode(N->getOpcode(), N->getDebugLoc(),
+                       N->getValueType(0).getScalarType(), Elt);
+  // Revectorize the result so the types line up with what the uses of this
+  // expression expect.
+  return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), N->getValueType(0),
+                     &Ops[0], 1);
+}
+
 /// ScalarizeVecOp_CONCAT_VECTORS - The vectors to concatenate have length one -
 /// use a BUILD_VECTOR instead.
 SDValue DAGTypeLegalizer::ScalarizeVecOp_CONCAT_VECTORS(SDNode *N) {
diff --git a/test/CodeGen/Thumb2/2013-03-06-vector-sext-operand-scalarize.ll b/test/CodeGen/Thumb2/2013-03-06-vector-sext-operand-scalarize.ll
new file mode 100644
index 0000000..203815f
--- /dev/null
+++ b/test/CodeGen/Thumb2/2013-03-06-vector-sext-operand-scalarize.ll
@@ -0,0 +1,19 @@
+; RUN: llc < %s -mtriple=thumbv7-apple-darwin | FileCheck %s
+
+; Testing that these don't crash/assert. The loop vectorizer can end up
+; with odd constructs like this. The code actually generated is incidental.
+define <1 x i64> @test_zext(i32 %a) nounwind {
+; CHECK: test_zext:
+  %Cmp = icmp uge i32 %a, 42
+  %vec = insertelement <1 x i1> zeroinitializer, i1 %Cmp, i32 0
+  %Se = zext <1 x i1> %vec to <1 x i64>
+  ret <1 x i64> %Se
+}
+
+define <1 x i64> @test_sext(i32 %a) nounwind {
+; CHECK: test_sext:
+  %Cmp = icmp uge i32 %a, 42
+  %vec = insertelement <1 x i1> zeroinitializer, i1 %Cmp, i32 0
+  %Se = sext <1 x i1> %vec to <1 x i64>
+  ret <1 x i64> %Se
+}