[llvm] r190830 - [SelectionDAG] Teach the vector scalarizer about TRUNCATE.

[Quentin Colombet]

Author: qcolombet
Date: Mon Sep 16 19:26:56 2013
New Revision: 190830

URL: http://llvm.org/viewvc/llvm-project?rev=190830&view=rev
Log:
[SelectionDAG] Teach the vector scalarizer about TRUNCATE.

When a truncate node defines a legal vector type but uses an illegal
vector type, the legalization process was splitting the vector until
<1 x vector> type, but then it was failing to scalarize the node because
it did not know how to handle TRUNCATE.

<rdar://problem/14989896>

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
    llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
    llvm/trunk/test/CodeGen/ARM/vector-DAGCombine.ll

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h?rev=190830&r1=190829&r2=190830&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h Mon Sep 16 19:26:56 2013
@@ -537,7 +537,7 @@ 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_UnaryOp(SDNode *N);
   SDValue ScalarizeVecOp_CONCAT_VECTORS(SDNode *N);
   SDValue ScalarizeVecOp_EXTRACT_VECTOR_ELT(SDNode *N);
   SDValue ScalarizeVecOp_STORE(StoreSDNode *N, unsigned OpNo);

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp?rev=190830&r1=190829&r2=190830&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp Mon Sep 16 19:26:56 2013
@@ -371,7 +371,8 @@ bool DAGTypeLegalizer::ScalarizeVectorOp
     case ISD::ANY_EXTEND:
     case ISD::ZERO_EXTEND:
     case ISD::SIGN_EXTEND:
-      Res = ScalarizeVecOp_EXTEND(N);
+    case ISD::TRUNCATE:
+      Res = ScalarizeVecOp_UnaryOp(N);
       break;
     case ISD::CONCAT_VECTORS:
       Res = ScalarizeVecOp_CONCAT_VECTORS(N);
@@ -410,7 +411,7 @@ SDValue DAGTypeLegalizer::ScalarizeVecOp
 
 /// 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) {
+SDValue DAGTypeLegalizer::ScalarizeVecOp_UnaryOp(SDNode *N) {
   assert(N->getValueType(0).getVectorNumElements() == 1 &&
          "Unexected vector type!");
   SDValue Elt = GetScalarizedVector(N->getOperand(0));

Modified: llvm/trunk/test/CodeGen/ARM/vector-DAGCombine.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/vector-DAGCombine.ll?rev=190830&r1=190829&r2=190830&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/vector-DAGCombine.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/vector-DAGCombine.ll Mon Sep 16 19:26:56 2013
@@ -224,3 +224,23 @@ entry:
   %vmull.i = tail call <8 x i16> @llvm.arm.neon.vmullu.v8i16(<8 x i8> %0, <8 x i8> %1)
   ret <8 x i16> %vmull.i
 }
+
+; <rdar://problem/14989896> Make sure we manage to truncate a vector from an
+; illegal type to a legal type.
+define <2 x i8> @test_truncate(<2 x i128> %in) {
+; CHECK-LABEL: test_truncate:
+; CHECK: mov [[BASE:r[0-9]+]], sp
+; CHECK-NEXT: vld1.32 {[[REG1:d[0-9]+]][0]}, {{\[}}[[BASE]]:32]
+; CHECK-NEXT: add [[BASE2:r[0-9]+]], [[BASE]], #4
+; CHECK-NEXT: vld1.32 {[[REG1]][1]}, {{\[}}[[BASE2]]:32]
+; REG2 Should map on the same Q register as REG1, i.e., REG2 = REG1 - 1, but we
+; cannot express that.
+; CHECK-NEXT: vmov.32 [[REG2:d[0-9]+]][0], r0
+; CHECK-NEXT: vmov.32 [[REG2]][1], r1
+; The Q register used here should match floor(REG1/2), but we cannot express that.
+; CHECK-NEXT: vmovn.i64 [[RES:d[0-9]+]], q{{[0-9]+}}
+; CHECK-NEXT: vmov r0, r1, [[RES]]
+entry:
+  %res = trunc <2 x i128> %in to <2 x i8>
+  ret <2 x i8> %res
+}