[CaptureTracking][NFC] Rename PASSTHROUGH to USER_MAY_CAPTURE

[sidorovd]

Summary

PASSTHROUGH is also a macro defined in wingdi.h, which is included in windows.h.
It's a follow up for https://reviews.llvm.org/D121272

[jdoerfert]

LG, next time upload it with full diff though.

llvm/include/llvm/Analysis/CaptureTracking.h

   enum class UseCaptureKind {
     NO_CAPTURE,
     MAY_CAPTURE,
-    PASSTHROUGH,
+    USER_MAY_CAPTURE,
   };
 
   /// Determine what kind of capture behaviour \p U may exhibit.

llvm/lib/Analysis/CaptureTracking.cpp

     // getUnderlyingObject in ValueTracking or DecomposeGEPExpression
     // in BasicAA also need to know about this property.
     if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(Call, true))
-      return UseCaptureKind::PASSTHROUGH;
+      return UseCaptureKind::USER_MAY_CAPTURE;
 
     // Volatile operations effectively capture the memory location that they
     // load and store to.

   case Instruction::Select:
   case Instruction::AddrSpaceCast:
     // The original value is not captured via this if the new value isn't.
-    return UseCaptureKind::PASSTHROUGH;
+    return UseCaptureKind::USER_MAY_CAPTURE;
   case Instruction::ICmp: {
     unsigned Idx = U.getOperandNo();
     unsigned OtherIdx = 1 - Idx;

       if (Tracker->captured(U))
         return;
       continue;
-    case UseCaptureKind::PASSTHROUGH:
+    case UseCaptureKind::USER_MAY_CAPTURE:
       if (!AddUses(U->getUser()))
         return;
       continue;

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

       return true;
     case UseCaptureKind::MAY_CAPTURE:
       return checkUse(A, T, U, Follow);
-    case UseCaptureKind::PASSTHROUGH:
+    case UseCaptureKind::USER_MAY_CAPTURE:
       Follow = true;
       return true;
     }