Cleanup CallConvLower.cpp

[pi1024e]

Summary

The CallConvLower code has a lot of jumps and incongruity in respect to the code's behavior despite there being functions that have identical behavior. For readability, and to highlight this, I refactored this file to better reflect that.

Not to mention, we do not need to assign to HaveRegParm until we go into the do-while loop.

[arsenm]

llvm/lib/CodeGen/CallingConvLower.cpp

192

Don't need the parens

[arsenm]

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llvm/lib/CodeGen/CallingConvLower.cpp

     return true; // Assume -msse-regparm might be in effect.
   if (!VT.isInteger())
     return false;
-  if (CC == CallingConv::X86_VectorCall || CC == CallingConv::X86_FastCall)
-    return true;
-  return false;
+  return (CC == CallingConv::X86_VectorCall || CC == CallingConv::X86_FastCall);
 }
 
 void CCState::getRemainingRegParmsForType(SmallVectorImpl<MCPhysReg> &Regs,

 
   // Allocate something of this value type repeatedly until we get assigned a
   // location in memory.
-  bool HaveRegParm = true;
-  while (HaveRegParm) {
+  bool HaveRegParm;
+  do {
     if (Fn(0, VT, VT, CCValAssign::Full, Flags, *this)) {
 #ifndef NDEBUG
       dbgs() << "Call has unhandled type " << EVT(VT).getEVTString()

       llvm_unreachable(nullptr);
     }
     HaveRegParm = Locs.back().isRegLoc();
-  }
+  } while (HaveRegParm);
 
   // Copy all the registers from the value locations we added.
   assert(NumLocs < Locs.size() && "CC assignment failed to add location");

     const TargetLowering *TL = MF.getSubtarget().getTargetLowering();
     const TargetRegisterClass *RC = TL->getRegClassFor(RegVT);
     for (MCPhysReg PReg : RemainingRegs) {
-      unsigned VReg = MF.addLiveIn(PReg, RC);
+      Register VReg = MF.addLiveIn(PReg, RC);
       Forwards.push_back(ForwardedRegister(VReg, PReg, RegVT));
     }
   }