[llvm] r223887 - LiveInterval: Add removeEmptySubRanges().

[Matthias Braun]

Author: matze
Date: Tue Dec  9 19:12:40 2014
New Revision: 223887

URL: http://llvm.org/viewvc/llvm-project?rev=223887&view=rev
Log:
LiveInterval: Add removeEmptySubRanges().

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

Modified: llvm/trunk/include/llvm/CodeGen/LiveInterval.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/LiveInterval.h?rev=223887&r1=223886&r2=223887&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/LiveInterval.h (original)
+++ llvm/trunk/include/llvm/CodeGen/LiveInterval.h Tue Dec  9 19:12:40 2014
@@ -669,6 +669,10 @@ namespace llvm {
       SubRanges = nullptr;
     }
 
+    /// Removes all subranges without any segments (subranges without segments
+    /// are not considered valid and should only exist temporarily).
+    void removeEmptySubRanges();
+
     /// getSize - Returns the sum of sizes of all the LiveRange's.
     ///
     unsigned getSize() const;

Modified: llvm/trunk/lib/CodeGen/LiveInterval.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveInterval.cpp?rev=223887&r1=223886&r2=223887&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveInterval.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveInterval.cpp Tue Dec  9 19:12:40 2014
@@ -592,6 +592,23 @@ VNInfo *LiveRange::MergeValueNumberInto(
   return V2;
 }
 
+void LiveInterval::removeEmptySubRanges() {
+  SubRange **NextPtr = &SubRanges;
+  SubRange *I = *NextPtr;
+  while (I != nullptr) {
+    if (!I->empty()) {
+      NextPtr = &I->Next;
+      I = *NextPtr;
+      continue;
+    }
+    // Skip empty subranges until we find the first nonempty one.
+    do {
+      I = I->Next;
+    } while (I != nullptr && I->empty());
+    *NextPtr = I;
+  }
+}
+
 unsigned LiveInterval::getSize() const {
   unsigned Sum = 0;
   for (const_iterator I = begin(), E = end(); I != E; ++I)