[ARM] MVE VMOV immediate handling

This adds some handling for VMOVimm, using the same method that NEON uses. We
create VMOVIMM/VMVNIMM/VMOVFPIMM nodes based on the immediate, and select them
using the now renamed ARMvmovImm/etc. There is also an extra 64bit immediate
mode that I have not yet added here.

Code by David Sherwood

Differential Revision: https://reviews.llvm.org/D63884

llvm-svn: 365178

1 files changed, 18 insertions, 9 deletions

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index ee760eb17a6..c66b8ce094a 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -823,9 +823,6 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM,
     setTargetDAGCombine(ISD::SIGN_EXTEND);
     setTargetDAGCombine(ISD::ZERO_EXTEND);
     setTargetDAGCombine(ISD::ANY_EXTEND);
-    setTargetDAGCombine(ISD::BUILD_VECTOR);
-    setTargetDAGCombine(ISD::VECTOR_SHUFFLE);
-    setTargetDAGCombine(ISD::INSERT_VECTOR_ELT);
     setTargetDAGCombine(ISD::STORE);
     setTargetDAGCombine(ISD::FP_TO_SINT);
     setTargetDAGCombine(ISD::FP_TO_UINT);
@@ -843,6 +840,12 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM,
     }
   }
 
+  if (Subtarget->hasNEON() || Subtarget->hasMVEIntegerOps()) {
+    setTargetDAGCombine(ISD::BUILD_VECTOR);
+    setTargetDAGCombine(ISD::VECTOR_SHUFFLE);
+    setTargetDAGCombine(ISD::INSERT_VECTOR_ELT);
+  }
+
   if (!Subtarget->hasFP64()) {
     // When targeting a floating-point unit with only single-precision
     // operations, f64 is legal for the few double-precision instructions which
@@ -5942,7 +5945,7 @@ static SDValue LowerSETCCCARRY(SDValue Op, SelectionDAG &DAG) {
 }
 
 /// isNEONModifiedImm - Check if the specified splat value corresponds to a
-/// valid vector constant for a NEON instruction with a "modified immediate"
+/// valid vector constant for a NEON or MVE instruction with a "modified immediate"
 /// operand (e.g., VMOV).  If so, return the encoded value.
 static SDValue isNEONModifiedImm(uint64_t SplatBits, uint64_t SplatUndef,
                                  unsigned SplatBitSize, SelectionDAG &DAG,
@@ -6028,6 +6031,10 @@ static SDValue isNEONModifiedImm(uint64_t SplatBits, uint64_t SplatUndef,
       break;
     }
 
+    // cmode == 0b1101 is not supported for MVE VMVN
+    if (type == MVEVMVNModImm)
+      return SDValue();
+
     if ((SplatBits & ~0xffffff) == 0 &&
         ((SplatBits | SplatUndef) & 0xffff) == 0xffff) {
       // Value = 0x00nnffff: Op=x, Cmode=1101.
@@ -6594,13 +6601,15 @@ SDValue ARMTargetLowering::LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG,
     if (SplatUndef.isAllOnesValue())
       return DAG.getUNDEF(VT);
 
-    if (ST->hasNEON() && SplatBitSize <= 64) {
+    if ((ST->hasNEON() && SplatBitSize <= 64) ||
+        (ST->hasMVEIntegerOps() && SplatBitSize <= 32)) {
       // Check if an immediate VMOV works.
       EVT VmovVT;
       SDValue Val = isNEONModifiedImm(SplatBits.getZExtValue(),
                                       SplatUndef.getZExtValue(), SplatBitSize,
                                       DAG, dl, VmovVT, VT.is128BitVector(),
                                       VMOVModImm);
+
       if (Val.getNode()) {
         SDValue Vmov = DAG.getNode(ARMISD::VMOVIMM, dl, VmovVT, Val);
         return DAG.getNode(ISD::BITCAST, dl, VT, Vmov);
@@ -6608,10 +6617,10 @@ SDValue ARMTargetLowering::LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG,
 
       // Try an immediate VMVN.
       uint64_t NegatedImm = (~SplatBits).getZExtValue();
-      Val = isNEONModifiedImm(NegatedImm,
-                                      SplatUndef.getZExtValue(), SplatBitSize,
-                                      DAG, dl, VmovVT, VT.is128BitVector(),
-                                      VMVNModImm);
+      Val = isNEONModifiedImm(
+          NegatedImm, SplatUndef.getZExtValue(), SplatBitSize,
+          DAG, dl, VmovVT, VT.is128BitVector(),
+          ST->hasMVEIntegerOps() ? MVEVMVNModImm : VMVNModImm);
       if (Val.getNode()) {
         SDValue Vmov = DAG.getNode(ARMISD::VMVNIMM, dl, VmovVT, Val);
         return DAG.getNode(ISD::BITCAST, dl, VT, Vmov);