+bool ARMFastISel::SelectIntCast(const Instruction *I) {
+ // On ARM, in general, integer casts don't involve legal types; this code
+ // handles promotable integers. The high bits for a type smaller than
+ // the register size are assumed to be undefined.
+ const Type *DestTy = I->getType();
+ Value *Op = I->getOperand(0);
+ const Type *SrcTy = Op->getType();
+
+ EVT SrcVT, DestVT;
+ SrcVT = TLI.getValueType(SrcTy, true);
+ DestVT = TLI.getValueType(DestTy, true);
+
+ if (isa<TruncInst>(I)) {
+ if (SrcVT != MVT::i32 && SrcVT != MVT::i16 && SrcVT != MVT::i8)
+ return false;
+ if (DestVT != MVT::i16 && DestVT != MVT::i8 && DestVT != MVT::i1)
+ return false;
+
+ unsigned SrcReg = getRegForValue(Op);
+ if (!SrcReg) return false;
+
+ // Because the high bits are undefined, a truncate doesn't generate
+ // any code.
+ UpdateValueMap(I, SrcReg);
+ return true;
+ }
+ if (DestVT != MVT::i32 && DestVT != MVT::i16 && DestVT != MVT::i8)
+ return false;
+
+ unsigned Opc;
+ bool isZext = isa<ZExtInst>(I);
+ bool isBoolZext = false;
+ if (!SrcVT.isSimple())
+ return false;
+ switch (SrcVT.getSimpleVT().SimpleTy) {
+ default: return false;
+ case MVT::i16:
+ if (isZext)
+ Opc = isThumb ? ARM::t2UXTHr : ARM::UXTHr;
+ else
+ Opc = isThumb ? ARM::t2SXTHr : ARM::SXTHr;
+ break;
+ case MVT::i8:
+ if (isZext)
+ Opc = isThumb ? ARM::t2UXTBr : ARM::UXTBr;
+ else
+ Opc = isThumb ? ARM::t2SXTBr : ARM::SXTBr;
+ break;
+ case MVT::i1:
+ if (isZext) {
+ Opc = isThumb ? ARM::t2ANDri : ARM::ANDri;
+ isBoolZext = true;
+ break;
+ }
+ return false;
+ }
+
+ // FIXME: We could save an instruction in many cases by special-casing
+ // load instructions.
+ unsigned SrcReg = getRegForValue(Op);
+ if (!SrcReg) return false;
+
+ unsigned DestReg = createResultReg(TLI.getRegClassFor(MVT::i32));
+ MachineInstrBuilder MIB;
+ MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(Opc), DestReg)
+ .addReg(SrcReg);
+ if (isBoolZext)
+ MIB.addImm(1);
+ AddOptionalDefs(MIB);
+ UpdateValueMap(I, DestReg);
+ return true;
+}
+