Fix code-gen crash on Power9 for insert_vector_elt with variable index (PR30189)

This patch corresponds to review:
https://reviews.llvm.org/D24021

In the initial implementation of this instruction, I forgot to account for
variable indices. This patch fixes PR30189 and should probably be merged into
3.9.1 (I'll open a bug according to the new instructions).

llvm-svn: 281479

3 files changed, 38 insertions, 2 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 170704958d4..4aed89ecbe9 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -667,9 +667,10 @@ PPCTargetLowering::PPCTargetLowering(const PPCTargetMachine &TM,
       addRegisterClass(MVT::v2i64, &PPC::VRRCRegClass);
       addRegisterClass(MVT::v1i128, &PPC::VRRCRegClass);
     }
+
     if (Subtarget.hasP9Vector()) {
-      setOperationAction(ISD::INSERT_VECTOR_ELT, MVT::v4i32, Legal);
-      setOperationAction(ISD::INSERT_VECTOR_ELT, MVT::v4f32, Legal);
+      setOperationAction(ISD::INSERT_VECTOR_ELT, MVT::v4i32, Custom);
+      setOperationAction(ISD::INSERT_VECTOR_ELT, MVT::v4f32, Custom);
     }
   }
 
@@ -7879,6 +7880,17 @@ SDValue PPCTargetLowering::LowerSCALAR_TO_VECTOR(SDValue Op,
   return DAG.getLoad(Op.getValueType(), dl, Store, FIdx, MachinePointerInfo());
 }
 
+SDValue PPCTargetLowering::LowerINSERT_VECTOR_ELT(SDValue Op,
+                                                  SelectionDAG &DAG) const {
+  assert(Op.getOpcode() == ISD::INSERT_VECTOR_ELT &&
+         "Should only be called for ISD::INSERT_VECTOR_ELT");
+  ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(2));
+  // We have legal lowering for constant indices but not for variable ones.
+  if (C)
+    return Op;
+  return SDValue();
+}
+
 SDValue PPCTargetLowering::LowerEXTRACT_VECTOR_ELT(SDValue Op,
                                                    SelectionDAG &DAG) const {
   SDLoc dl(Op);
@@ -8284,6 +8296,7 @@ SDValue PPCTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::SCALAR_TO_VECTOR:   return LowerSCALAR_TO_VECTOR(Op, DAG);
   case ISD::SIGN_EXTEND_INREG:  return LowerSIGN_EXTEND_INREG(Op, DAG);
   case ISD::EXTRACT_VECTOR_ELT: return LowerEXTRACT_VECTOR_ELT(Op, DAG);
+  case ISD::INSERT_VECTOR_ELT:  return LowerINSERT_VECTOR_ELT(Op, DAG);
   case ISD::MUL:                return LowerMUL(Op, DAG);
 
   // For counter-based loop handling.
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
index 8b1c22b6bcd..83a7a3faf36 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -849,6 +849,7 @@ namespace llvm {
     SDValue LowerSRA_PARTS(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerINSERT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerEXTRACT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerSCALAR_TO_VECTOR(SDValue Op, SelectionDAG &DAG) const;
diff --git a/llvm/test/CodeGen/PowerPC/p9-xxinsertw-xxextractuw.ll b/llvm/test/CodeGen/PowerPC/p9-xxinsertw-xxextractuw.ll
index ac187e08425..fa2844b8d55 100644
--- a/llvm/test/CodeGen/PowerPC/p9-xxinsertw-xxextractuw.ll
+++ b/llvm/test/CodeGen/PowerPC/p9-xxinsertw-xxextractuw.ll
@@ -968,3 +968,25 @@ entry:
   %vecins = shufflevector <4 x float> %a, <4 x float> %a, <4 x i32> <i32 0, i32 1, i32 2, i32 6>
   ret <4 x float> %vecins
 }
+define <4 x float> @insertVarF(<4 x float> %a, float %f, i32 %el) {
+entry:
+; CHECK-LABEL: insertVarF
+; CHECK: stxsspx 1,
+; CHECK: lxvd2x
+; CHECK-BE-LABEL: insertVarF
+; CHECK-BE: stxsspx 1,
+; CHECK-BE: lxvw4x
+  %vecins = insertelement <4 x float> %a, float %f, i32 %el
+  ret <4 x float> %vecins
+}
+define <4 x i32> @insertVarI(<4 x i32> %a, i32 %i, i32 %el) {
+entry:
+; CHECK-LABEL: insertVarI
+; CHECK: stwx
+; CHECK: lxvd2x
+; CHECK-BE-LABEL: insertVarI
+; CHECK-BE: stwx
+; CHECK-BE: lxvw4x
+  %vecins = insertelement <4 x i32> %a, i32 %i, i32 %el
+  ret <4 x i32> %vecins
+}