[llvm] Compare std::optional<T> to values directly (NFC) (#143913)

This patch transforms:

  X && *X == Y

to:

  X == Y

where X is of std::optional<T>, and Y is of T or similar.

Author: kazutakahirata

llvm/lib/Analysis/ConstantFolding.cpp

@@ -2132,7 +2132,7 @@ static bool mayFoldConstrained(ConstrainedFPIntrinsic *CI,
 
   // If evaluation raised FP exception, the result can depend on rounding
   // mode. If the latter is unknown, folding is not possible.
-  if (ORM && *ORM == RoundingMode::Dynamic)
+  if (ORM == RoundingMode::Dynamic)
     return false;
 
   // If FP exceptions are ignored, fold the call, even if such exception is
@@ -2418,7 +2418,7 @@ static Constant *ConstantFoldScalarCall1(StringRef Name,
         if (IntrinsicID == Intrinsic::experimental_constrained_rint &&
             St == APFloat::opInexact) {
           std::optional<fp::ExceptionBehavior> EB = CI->getExceptionBehavior();
-          if (EB && *EB == fp::ebStrict)
+          if (EB == fp::ebStrict)
             return nullptr;
         }
       } else if (U.isSignaling()) {

llvm/lib/IR/Attributes.cpp

@@ -295,7 +295,7 @@ Attribute Attribute::getWithCaptureInfo(LLVMContext &Context, CaptureInfo CI) {
 Attribute
 Attribute::getWithAllocSizeArgs(LLVMContext &Context, unsigned ElemSizeArg,
                                 const std::optional<unsigned> &NumElemsArg) {
-  assert(!(ElemSizeArg == 0 && NumElemsArg && *NumElemsArg == 0) &&
+  assert(!(ElemSizeArg == 0 && NumElemsArg == 0) &&
          "Invalid allocsize arguments -- given allocsize(0, 0)");
   return get(Context, AllocSize, packAllocSizeArgs(ElemSizeArg, NumElemsArg));
 }