[CodeGen][SDAG] Track returntwice in lowering info (#92640)

This saves an extra iteration over the all instructions of the function.

Author: aengelke

llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp

@@ -214,6 +214,10 @@ void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
           if (CI->isMustTailCall() && Fn->isVarArg())
             MF->getFrameInfo().setHasMustTailInVarArgFunc(true);
         }
+
+        // Determine if there is a call to setjmp in the machine function.
+        if (Call->hasFnAttr(Attribute::ReturnsTwice))
+          MF->setExposesReturnsTwice(true);
       }
 
       // Mark values used outside their block as exported, by allocating

llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

@@ -680,9 +680,6 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
     }
   }
 
-  // Determine if there is a call to setjmp in the machine function.
-  MF->setExposesReturnsTwice(Fn.callsFunctionThatReturnsTwice());
-
   // Determine if floating point is used for msvc
   computeUsesMSVCFloatingPoint(TM.getTargetTriple(), Fn, MF->getMMI());