Verify that one of the ranges produced by region splitting is allocatable.
We should not be attempting a region split if it won't lead to at least one
directly allocatable interval. That could cause infinite splitting loops.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124893 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 2c772a2..f478d76 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -812,8 +812,22 @@
// separate into connected components. Some components may be allocatable.
SE.finish();
- if (VerifyEnabled)
+ if (VerifyEnabled) {
MF->verify(this, "After splitting live range around region");
+
+#ifndef NDEBUG
+ // Make sure that at least one of the new intervals can allocate to PhysReg.
+ // That was the whole point of splitting the live range.
+ bool found = false;
+ for (LiveRangeEdit::iterator I = LREdit.begin(), E = LREdit.end(); I != E;
+ ++I)
+ if (!checkUncachedInterference(**I, PhysReg)) {
+ found = true;
+ break;
+ }
+ assert(found && "No allocatable intervals after pointless splitting");
+#endif
+ }
}
unsigned RAGreedy::tryRegionSplit(LiveInterval &VirtReg, AllocationOrder &Order,