From 2ce63c73520cd6e715f9114589f802938b5db01f Mon Sep 17 00:00:00 2001
From: Pete Cooper <peter_cooper@apple.com>
Date: Tue, 3 Apr 2012 22:57:55 +0000
Subject: [PATCH] Add VSELECT to LegalizeVectorTypes::ScalariseVectorResult. 
 Previously it would crash if it encountered a 1 element VSELECT.  Solution is
 slightly more complicated than just creating a SELET as we have to mask or
 sign extend the vector condition if it had different boolean contents from
 the scalar condition.  Fixes <rdar://problem/11178095>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153976 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/LegalizeTypes.h      |  1 +
 .../SelectionDAG/LegalizeVectorTypes.cpp      | 33 +++++++++++++++++++
 test/CodeGen/Generic/select.ll                |  8 +++++
 3 files changed, 42 insertions(+)

diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index 69c21000015..e8664458e9a 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -521,6 +521,7 @@ private:
   SDValue ScalarizeVecRes_LOAD(LoadSDNode *N);
   SDValue ScalarizeVecRes_SCALAR_TO_VECTOR(SDNode *N);
   SDValue ScalarizeVecRes_SIGN_EXTEND_INREG(SDNode *N);
+  SDValue ScalarizeVecRes_VSELECT(SDNode *N);
   SDValue ScalarizeVecRes_SELECT(SDNode *N);
   SDValue ScalarizeVecRes_SELECT_CC(SDNode *N);
   SDValue ScalarizeVecRes_SETCC(SDNode *N);
diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index a8aee122788..aa92cc3638b 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -58,6 +58,7 @@ void DAGTypeLegalizer::ScalarizeVectorResult(SDNode *N, unsigned ResNo) {
   case ISD::LOAD:           R = ScalarizeVecRes_LOAD(cast<LoadSDNode>(N));break;
   case ISD::SCALAR_TO_VECTOR:  R = ScalarizeVecRes_SCALAR_TO_VECTOR(N); break;
   case ISD::SIGN_EXTEND_INREG: R = ScalarizeVecRes_InregOp(N); break;
+  case ISD::VSELECT:           R = ScalarizeVecRes_VSELECT(N); break;
   case ISD::SELECT:            R = ScalarizeVecRes_SELECT(N); break;
   case ISD::SELECT_CC:         R = ScalarizeVecRes_SELECT_CC(N); break;
   case ISD::SETCC:             R = ScalarizeVecRes_SETCC(N); break;
@@ -226,6 +227,38 @@ SDValue DAGTypeLegalizer::ScalarizeVecRes_SCALAR_TO_VECTOR(SDNode *N) {
   return InOp;
 }
 
+SDValue DAGTypeLegalizer::ScalarizeVecRes_VSELECT(SDNode *N) {
+  SDValue Cond = GetScalarizedVector(N->getOperand(0));
+  SDValue LHS = GetScalarizedVector(N->getOperand(1));
+  TargetLowering::BooleanContent ScalarBool = TLI.getBooleanContents(false);
+  TargetLowering::BooleanContent VecBool = TLI.getBooleanContents(true);
+  if (ScalarBool != VecBool) {
+    EVT CondVT = Cond.getValueType();
+    switch (ScalarBool) {
+      default: llvm_unreachable("Unknown boolean content enum");
+      case TargetLowering::UndefinedBooleanContent:
+        break;
+      case TargetLowering::ZeroOrOneBooleanContent:
+        assert(VecBool == TargetLowering::UndefinedBooleanContent ||
+               VecBool == TargetLowering::ZeroOrNegativeOneBooleanContent);
+        // Vector read from all ones, scalar expects a single 1 so mask.
+        Cond = DAG.getNode(ISD::AND, N->getDebugLoc(), CondVT,
+                           Cond, DAG.getConstant(1, CondVT));
+        break;
+      case TargetLowering::ZeroOrNegativeOneBooleanContent:
+        assert(VecBool == TargetLowering::UndefinedBooleanContent ||
+               VecBool == TargetLowering::ZeroOrOneBooleanContent);
+        // Vector reads from a one, scalar from all ones so sign extend.
+        Cond = DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), CondVT,
+                           Cond, DAG.getValueType(MVT::i1));
+        break;
+    }
+  }
+  return DAG.getNode(ISD::SELECT, N->getDebugLoc(),
+                     LHS.getValueType(), Cond, LHS,
+                     GetScalarizedVector(N->getOperand(2)));
+}
+
 SDValue DAGTypeLegalizer::ScalarizeVecRes_SELECT(SDNode *N) {
   SDValue LHS = GetScalarizedVector(N->getOperand(1));
   return DAG.getNode(ISD::SELECT, N->getDebugLoc(),
diff --git a/test/CodeGen/Generic/select.ll b/test/CodeGen/Generic/select.ll
index 63052c1a284..77636eb6e61 100644
--- a/test/CodeGen/Generic/select.ll
+++ b/test/CodeGen/Generic/select.ll
@@ -185,3 +185,11 @@ define i32 @checkFoldGEP(%Domain* %D, i64 %idx) {
         ret i32 %reg820
 }
 
+; Test case for scalarising a 1 element vselect
+;
+define <1 x i32> @checkScalariseVSELECT(<1 x i32> %a, <1 x i32> %b) {
+        %cond = icmp uge <1 x i32> %a, %b
+        %s = select <1 x i1> %cond, <1 x i32> %a, <1 x i32> %b
+        ret <1 x i32> %s
+}
+