Also compute MBB live-in lists in the new rewriter pass.
This deduplicates some code from the optimizing register allocators, and
it means that it is now possible to change the register allocators'
solutions simply by editing the VirtRegMap between the register
allocator pass and the rewriter.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158249 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index 45c7dd0..93840f0 100644
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -203,6 +203,9 @@
// Add kill flags while we still have virtual registers.
LIS->addKillFlags();
+ // Live-in lists on basic blocks are required for physregs.
+ addMBBLiveIns();
+
// Rewrite virtual registers.
rewrite();
@@ -216,6 +219,35 @@
return true;
}
+// Compute MBB live-in lists from virtual register live ranges and their
+// assignments.
+void VirtRegRewriter::addMBBLiveIns() {
+ SmallVector<MachineBasicBlock*, 16> LiveIn;
+ for (unsigned Idx = 0, IdxE = MRI->getNumVirtRegs(); Idx != IdxE; ++Idx) {
+ unsigned VirtReg = TargetRegisterInfo::index2VirtReg(Idx);
+ if (MRI->reg_nodbg_empty(VirtReg))
+ continue;
+ LiveInterval &LI = LIS->getInterval(VirtReg);
+ if (LI.empty() || LIS->intervalIsInOneMBB(LI))
+ continue;
+ // This is a virtual register that is live across basic blocks. Its
+ // assigned PhysReg must be marked as live-in to those blocks.
+ unsigned PhysReg = VRM->getPhys(VirtReg);
+ assert(PhysReg != VirtRegMap::NO_PHYS_REG && "Unmapped virtual register.");
+
+ // Scan the segments of LI.
+ for (LiveInterval::const_iterator I = LI.begin(), E = LI.end(); I != E;
+ ++I) {
+ if (!Indexes->findLiveInMBBs(I->start, I->end, LiveIn))
+ continue;
+ for (unsigned i = 0, e = LiveIn.size(); i != e; ++i)
+ if (!LiveIn[i]->isLiveIn(PhysReg))
+ LiveIn[i]->addLiveIn(PhysReg);
+ LiveIn.clear();
+ }
+ }
+}
+
void VirtRegRewriter::rewrite() {
SmallVector<unsigned, 8> SuperDeads;
SmallVector<unsigned, 8> SuperDefs;