[llvm] r254371 - RegisterPressure: Remove support for recede()/advance() at MBB boundaries

[Matthias Braun via llvm-commits]

Author: matze
Date: Mon Nov 30 22:20:04 2015
New Revision: 254371

URL: http://llvm.org/viewvc/llvm-project?rev=254371&view=rev
Log:
RegisterPressure: Remove support for recede()/advance() at MBB boundaries

Nobody was checking the returnvalue of recede()/advance() so we can
simply replace this code with asserts.

Modified:
    llvm/trunk/include/llvm/CodeGen/RegisterPressure.h
    llvm/trunk/lib/CodeGen/RegisterPressure.cpp

Modified: llvm/trunk/include/llvm/CodeGen/RegisterPressure.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/RegisterPressure.h?rev=254371&r1=254370&r2=254371&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/RegisterPressure.h (original)
+++ llvm/trunk/include/llvm/CodeGen/RegisterPressure.h Mon Nov 30 22:20:04 2015
@@ -329,11 +329,11 @@ public:
   void setPos(MachineBasicBlock::const_iterator Pos) { CurrPos = Pos; }
 
   /// Recede across the previous instruction.
-  bool recede(SmallVectorImpl<unsigned> *LiveUses = nullptr,
+  void recede(SmallVectorImpl<unsigned> *LiveUses = nullptr,
               PressureDiff *PDiff = nullptr);
 
   /// Advance across the current instruction.
-  bool advance();
+  void advance();
 
   /// Finalize the region boundaries and recored live ins and live outs.
   void closeRegion();
@@ -350,8 +350,7 @@ public:
   ArrayRef<unsigned> getLiveThru() const { return LiveThruPressure; }
 
   /// Get the resulting register pressure over the traversed region.
-  /// This result is complete if either advance() or recede() has returned true,
-  /// or if closeRegion() was explicitly invoked.
+  /// This result is complete if closeRegion() was explicitly invoked.
   RegisterPressure &getPressure() { return P; }
   const RegisterPressure &getPressure() const { return P; }
 

Modified: llvm/trunk/lib/CodeGen/RegisterPressure.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegisterPressure.cpp?rev=254371&r1=254370&r2=254371&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegisterPressure.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegisterPressure.cpp Mon Nov 30 22:20:04 2015
@@ -491,13 +491,9 @@ void RegPressureTracker::discoverLiveOut
 /// registers that are both defined and used by the instruction.  If a pressure
 /// difference pointer is provided record the changes is pressure caused by this
 /// instruction independent of liveness.
-bool RegPressureTracker::recede(SmallVectorImpl<unsigned> *LiveUses,
+void RegPressureTracker::recede(SmallVectorImpl<unsigned> *LiveUses,
                                 PressureDiff *PDiff) {
-  // Check for the top of the analyzable region.
-  if (CurrPos == MBB->begin()) {
-    closeRegion();
-    return false;
-  }
+  assert(CurrPos != MBB->begin());
   if (!isBottomClosed())
     closeBottom();
 
@@ -509,11 +505,8 @@ bool RegPressureTracker::recede(SmallVec
   do
     --CurrPos;
   while (CurrPos != MBB->begin() && CurrPos->isDebugValue());
+  assert(!CurrPos->isDebugValue());
 
-  if (CurrPos->isDebugValue()) {
-    closeRegion();
-    return false;
-  }
   SlotIndex SlotIdx;
   if (RequireIntervals)
     SlotIdx = LIS->getInstructionIndex(CurrPos).getRegSlot();
@@ -584,18 +577,13 @@ bool RegPressureTracker::recede(SmallVec
         UntiedDefs.insert(Reg);
     }
   }
-  return true;
 }
 
 /// Advance across the current instruction.
-bool RegPressureTracker::advance() {
+void RegPressureTracker::advance() {
   assert(!TrackUntiedDefs && "unsupported mode");
 
-  // Check for the bottom of the analyzable region.
-  if (CurrPos == MBB->end()) {
-    closeRegion();
-    return false;
-  }
+  assert(CurrPos != MBB->end());
   if (!isTopClosed())
     closeTop();
 
@@ -653,7 +641,6 @@ bool RegPressureTracker::advance() {
   do
     ++CurrPos;
   while (CurrPos != MBB->end() && CurrPos->isDebugValue());
-  return true;
 }
 
 /// Find the max change in excess pressure across all sets.