Added recognition for signed add/sub/mul with overflow intrinsics to …

…GVN as per Chris and Frits suggestion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134777 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/GVN.cpp

@@ -173,12 +173,15 @@ Expression ValueTable::create_extractvalue_expression(ExtractValueInst *EI) {
     // is we'll synthesize a semantically equivalent expression instead on
     // an extract value expression.
     switch (I->getIntrinsicID()) {
+      case Intrinsic::sadd_with_overflow:
       case Intrinsic::uadd_with_overflow:
         e.opcode = Instruction::Add;
         break;
+      case Intrinsic::ssub_with_overflow:
       case Intrinsic::usub_with_overflow:
         e.opcode = Instruction::Sub;
         break;
+      case Intrinsic::smul_with_overflow:
       case Intrinsic::umul_with_overflow:
         e.opcode = Instruction::Mul;
         break;