Committing a good chunk of the pre-register allocation live interval splitting pass. It's handling simple cases and appear to do good things. Next: avoid splitting an interval multiple times; renumber registers when possible; record stack slot live intervals for coloring; rematerialize defs when possible.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58044 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp
index ede387e..c382a4a 100644
--- a/lib/CodeGen/RegAllocLinearScan.cpp
+++ b/lib/CodeGen/RegAllocLinearScan.cpp
@@ -49,6 +49,11 @@
cl::desc("Use new spilling heuristic"),
cl::init(false), cl::Hidden);
+static cl::opt<bool>
+PreSplitIntervals("pre-alloc-split",
+ cl::desc("Pre-register allocation live interval splitting"),
+ cl::init(false), cl::Hidden);
+
static RegisterRegAlloc
linearscanRegAlloc("linearscan", "linear scan register allocator",
createLinearScanRegisterAllocator);
@@ -113,6 +118,8 @@
// Make sure PassManager knows which analyses to make available
// to coalescing and which analyses coalescing invalidates.
AU.addRequiredTransitive<RegisterCoalescer>();
+ if (PreSplitIntervals)
+ AU.addRequiredID(PreAllocSplittingID);
AU.addRequired<LiveStacks>();
AU.addPreserved<LiveStacks>();
AU.addRequired<MachineLoopInfo>();