[OMPIRBuilder] Remove the support for floating point values for atomic compare operation

[tianshilei1992]

Summary

This patch removes the type punning in atomic compare operation for
floating point values because the direct comparison doesn't make too much sense
for floating point values.

[jdoerfert]

LG

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

 OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::createAtomicCompare(
     const LocationDescription &Loc, AtomicOpValue &X, Value *E, Value *D,
     AtomicOrdering AO, OMPAtomicCompareOp Op, bool IsXBinopExpr) {
   if (!updateToLocation(Loc))
     return Loc.IP;
 
   assert(X.Var->getType()->isPointerTy() &&
          "OMP atomic expects a pointer to target memory");
-  assert((X.ElemTy->isFloatingPointTy() || X.ElemTy->isIntegerTy() ||
-          X.ElemTy->isPointerTy()) &&
-         "OMP atomic compare expected a scalar type");
+  assert((X.ElemTy->isIntegerTy() || X.ElemTy->isPointerTy()) &&
+         "OMP atomic compare expected a integer scalar type");
 
   if (Op == OMPAtomicCompareOp::EQ) {
-    unsigned Addrspace = cast<PointerType>(X.Var->getType())->getAddressSpace();
-    IntegerType *IntCastTy =
-        IntegerType::get(M.getContext(), X.ElemTy->getScalarSizeInBits());
-    Value *XAddr =
-        X.ElemTy->isIntegerTy()
-            ? X.Var
-            : Builder.CreateBitCast(X.Var, IntCastTy->getPointerTo(Addrspace));
     AtomicOrdering Failure = AtomicCmpXchgInst::getStrongestFailureOrdering(AO);
     // We don't need the result for now.
-    (void)Builder.CreateAtomicCmpXchg(XAddr, E, D, MaybeAlign(), AO, Failure);
+    (void)Builder.CreateAtomicCmpXchg(X.Var, E, D, MaybeAlign(), AO, Failure);
   } else {
     assert((Op == OMPAtomicCompareOp::MAX || Op == OMPAtomicCompareOp::MIN) &&
            "Op should be either max or min at this point");
-    assert(X.ElemTy->isIntegerTy() &&
-           "max and min operators only support integer type");
 
     // Reverse the ordop as the OpenMP forms are different from LLVM forms.
     // Let's take max as example.
     // OpenMP form:
     // x = x > expr ? expr : x;
     // LLVM form:
     // *ptr = *ptr > val ? *ptr : val;
     // We need to transform to LLVM form.