[AArch64] Mark FMOVvXfY_ns as rematerializable, cheap

Otherwise, the register allocator may spill and reload constants that
can be rematerialized with a single instruction.

Author: guy-david

llvm/lib/Target/AArch64/AArch64InstrInfo.td

@@ -8354,6 +8354,7 @@ def : InstAlias<"orr.4s $Vd, $imm", (ORRv4i32 V128:$Vd, imm0_255:$imm, 0)>;
 }
 
 // AdvSIMD FMOV
+let isReMaterializable = 1, isAsCheapAsAMove = 1 in {
 def FMOVv2f64_ns : SIMDModifiedImmVectorNoShift<1, 1, 0, 0b1111, V128, fpimm8,
                                               "fmov", ".2d",
                        [(set (v2f64 V128:$Rd), (AArch64fmov imm0_255:$imm8))]>;
@@ -8371,6 +8372,7 @@ def FMOVv8f16_ns : SIMDModifiedImmVectorNoShift<1, 0, 1, 0b1111, V128, fpimm8,
                                               "fmov", ".8h",
                        [(set (v8f16 V128:$Rd), (AArch64fmov imm0_255:$imm8))]>;
 } // Predicates = [HasNEON, HasFullFP16]
+}
 
 // AdvSIMD MOVI