[ARM] VMOVrh of VMOVhr

A VMOVhr of a VMOVrh can be simply folded to the original HPR value.

Differential Revision: https://reviews.llvm.org/D78710

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index a1ca6d9..3da5615 100644 (file)
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -13030,13 +13030,18 @@ static SDValue PerformVMOVDRRCombine(SDNode *N, SelectionDAG &DAG) {
 }
 
 static SDValue PerformVMOVhrCombine(SDNode *N, TargetLowering::DAGCombinerInfo &DCI) {
+  SDValue Op0 = N->getOperand(0);
+
+  // VMOVhr (VMOVrh (X)) -> X
+  if (Op0->getOpcode() == ARMISD::VMOVrh)
+    return Op0->getOperand(0);
+
   // FullFP16: half values are passed in S-registers, and we don't
   // need any of the bitcast and moves:
   //
   //     t2: f32,ch = CopyFromReg t0, Register:f32 %0
   //   t5: i32 = bitcast t2
   // t18: f16 = ARMISD::VMOVhr t5
-  SDValue Op0 = N->getOperand(0);
   if (Op0->getOpcode() == ISD::BITCAST) {
     SDValue Copy = Op0->getOperand(0);
     if (Copy.getValueType() == MVT::f32 &&

diff --git a/llvm/test/CodeGen/Thumb2/mve-vdup.ll b/llvm/test/CodeGen/Thumb2/mve-vdup.ll
index de680e6..06dc296 100644 (file)
--- a/llvm/test/CodeGen/Thumb2/mve-vdup.ll
+++ b/llvm/test/CodeGen/Thumb2/mve-vdup.ll
@@ -256,8 +256,6 @@ define arm_aapcs_vfpcc half @vdup_f16_extract(half* %src1, half* %src2) {
 ; CHECK-NEXT:    vldr.16 s0, [r2]
 ; CHECK-NEXT:    vldr.16 s2, [r1]
 ; CHECK-NEXT:    vadd.f16 s0, s2, s0
-; CHECK-NEXT:    vmov.f16 r1, s0
-; CHECK-NEXT:    vmov.f16 s0, r1
 ; CHECK-NEXT:    vstr.16 s0, [r0]
 ; CHECK-NEXT:    bx lr
 entry: