[llvm] [llvm] Add floating point exception status for APFloat's exp function. (PR #203066)

[via llvm-commits]

================
@@ -6093,22 +6094,53 @@ APFloat::Storage &APFloat::Storage::operator=(APFloat::Storage &&RHS) {
   return *this;
 }
 
+namespace {
+
+APFloat::opStatus getOpStatusFromLibc(int libc_exceptions) {
+  APFloat::opStatus status = APFloat::opOK;
+  if (libc_exceptions & FE_INVALID)
+    status = static_cast<APFloat::opStatus>(status | APFloat::opInvalidOp);
+  if (libc_exceptions & FE_DIVBYZERO)
+    status = static_cast<APFloat::opStatus>(status | APFloat::opDivByZero);
+  if (libc_exceptions & FE_OVERFLOW)
+    status = static_cast<APFloat::opStatus>(status | APFloat::opOverflow);
+  if (libc_exceptions & FE_UNDERFLOW)
+    status = static_cast<APFloat::opStatus>(status | APFloat::opUnderflow);
+  if (libc_exceptions & FE_INEXACT)
+    status = static_cast<APFloat::opStatus>(status | APFloat::opInexact);
+  return status;
+}
+
+} // namespace
+
 // TODO: Support other rounding modes when LLVM libc math implement static
 // roundings.
-APFloat exp(const APFloat &X, RoundingMode rounding_mode) {
+std::optional<APFloat> exp(const APFloat &X, RoundingMode rounding_mode,
+                           APFloat::opStatus *Status) {
+
   if (rounding_mode == APFloatBase::rmNearestTiesToEven) {
     if (APFloat::SemanticsToEnum(X.getSemantics()) ==
         APFloatBase::S_IEEEsingle) {
-      float result = LIBC_NAMESPACE::shared::expf(X.convertToFloat());
+      float x_val = X.convertToFloat();
+      int exc =
+          LIBC_NAMESPACE::shared::check::exp_exceptions(x_val, FE_TONEAREST);
----------------
lntue wrote:

It is a template defined at https://github.com/llvm/llvm-project/blob/main/libc/src/__support/math/check/exp_exceptions.h#L59
It was added in https://github.com/llvm/llvm-project/pull/202503 to centralize floating exception checking without involving fenv.

https://github.com/llvm/llvm-project/pull/203066