diff options
| -rw-r--r-- | lib/CodeGen/SpillPlacement.cpp | 1 | ||||
| -rw-r--r-- | lib/CodeGen/SpillPlacement.h | 11 |
2 files changed, 11 insertions, 1 deletions
diff --git a/lib/CodeGen/SpillPlacement.cpp b/lib/CodeGen/SpillPlacement.cpp index ce7b37bfce..10a3c18962 100644 --- a/lib/CodeGen/SpillPlacement.cpp +++ b/lib/CodeGen/SpillPlacement.cpp @@ -220,6 +220,7 @@ void SpillPlacement::addConstraints(ArrayRef<BlockConstraint> LiveBlocks) { 0, // DontCare, 1, // PrefReg, -1, // PrefSpill + 0, // PrefBoth -HUGE_VALF // MustSpill }; diff --git a/lib/CodeGen/SpillPlacement.h b/lib/CodeGen/SpillPlacement.h index 9a4fc6dc97..9d1d676c54 100644 --- a/lib/CodeGen/SpillPlacement.h +++ b/lib/CodeGen/SpillPlacement.h @@ -71,6 +71,7 @@ public: DontCare, ///< Block doesn't care / variable not live. PrefReg, ///< Block entry/exit prefers a register. PrefSpill, ///< Block entry/exit prefers a stack slot. + PrefBoth, ///< Block entry prefers both register and stack. MustSpill ///< A register is impossible, variable must be spilled. }; @@ -79,6 +80,11 @@ public: unsigned Number; ///< Basic block number (from MBB::getNumber()). BorderConstraint Entry : 8; ///< Constraint on block entry. BorderConstraint Exit : 8; ///< Constraint on block exit. + + /// True when this block changes the value of the live range. This means + /// the block has a non-PHI def. When this is false, a live-in value on + /// the stack can be live-out on the stack without inserting a spill. + bool ChangesValue; }; /// prepare - Reset state and prepare for a new spill placement computation. @@ -96,7 +102,10 @@ public: /// live out. void addConstraints(ArrayRef<BlockConstraint> LiveBlocks); - /// addPrefSpill - Add PrefSpill constraints to all blocks listed. + /// addPrefSpill - Add PrefSpill constraints to all blocks listed. This is + /// equivalent to calling addConstraint with identical BlockConstraints with + /// Entry = Exit = PrefSpill, and ChangesValue = false. + /// /// @param Blocks Array of block numbers that prefer to spill in and out. void addPrefSpill(ArrayRef<unsigned> Blocks); |