$ svn merge -c 113848 https://llvm.org/svn/llvm-project/llvm/trunk

--- Merging r113848 into '.':
U    lib/CodeGen/PeepholeOptimizer.cpp

must not peephole away side effects

llvm-svn: 113913

Author: isanbard

llvm/lib/CodeGen/PeepholeOptimizer.cpp

@@ -272,7 +272,8 @@ bool PeepholeOptimizer::runOnMachineFunction(MachineFunction &MF) {
            MII = I->begin(), ME = I->end(); MII != ME; ) {
       MachineInstr *MI = &*MII;
 
-      if (MI->getDesc().isCompare()) {
+      if (MI->getDesc().isCompare() &&
+          !MI->getDesc().hasUnmodeledSideEffects()) {
         ++MII; // The iterator may become invalid if the compare is deleted.
         Changed |= OptimizeCmpInstr(MI, MBB);
       } else {