Cherry-pick r236569 from upstream

lib/Target/ARM/ARMFastISel.cpp

 //===-- ARMFastISel.cpp - ARM FastISel implementation ---------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file defines the ARM-specific support for the FastISel class. Some
@@ skipping 1654 matching lines @@
     UseImm = isThumb2 ? (ARM_AM::getT2SOImmVal(Imm) != -1) :
       (ARM_AM::getSOImmVal(Imm) != -1);
   }
 
   unsigned Op2Reg = 0;
   if (!UseImm) {
     Op2Reg = getRegForValue(I->getOperand(2));
     if (Op2Reg == 0) return false;
   }
 
-  unsigned CmpOpc = isThumb2 ? ARM::t2CMPri : ARM::CMPri;
-  CondReg = constrainOperandRegClass(TII.get(CmpOpc), CondReg, 0);
+  unsigned TstOpc = isThumb2 ? ARM::t2TSTri : ARM::TSTri;
+  CondReg = constrainOperandRegClass(TII.get(TstOpc), CondReg, 0);
   AddOptionalDefs(
-      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(CmpOpc))
+      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(TstOpc))
           .addReg(CondReg)
-          .addImm(0));
+          .addImm(1));
 
   unsigned MovCCOpc;
   const TargetRegisterClass *RC;
   if (!UseImm) {
     RC = isThumb2 ? &ARM::tGPRRegClass : &ARM::GPRRegClass;
     MovCCOpc = isThumb2 ? ARM::t2MOVCCr : ARM::MOVCCr;
   } else {
     RC = isThumb2 ? &ARM::rGPRRegClass : &ARM::GPRRegClass;
     if (!isNegativeImm)
       MovCCOpc = isThumb2 ? ARM::t2MOVCCi : ARM::MOVCCi;
@@ skipping 1398 matching lines @@
       // iOS always has a FP for backtracking, force other targets
       // to keep their FP when doing FastISel. The emitted code is
       // currently superior, and in cases like test-suite's lencod
       // FastISel isn't quite correct when FP is eliminated.
       TM.Options.NoFramePointerElim = true;
       return new ARMFastISel(funcInfo, libInfo);
     }
     return nullptr;
   }
 }