BranchRelaxation: Recompute live-ins when splitting a block
Factors out and reuses live-in computation code from BranchFolding.
Differential Revision: https://reviews.llvm.org/D27558
llvm-svn: 290013
diff --git a/llvm/lib/CodeGen/BranchRelaxation.cpp b/llvm/lib/CodeGen/BranchRelaxation.cpp
index 244c01c..8b27570 100644
--- a/llvm/lib/CodeGen/BranchRelaxation.cpp
+++ b/llvm/lib/CodeGen/BranchRelaxation.cpp
@@ -10,6 +10,7 @@
#include "llvm/CodeGen/Passes.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/LivePhysRegs.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/Target/TargetInstrInfo.h"
@@ -69,8 +70,10 @@
SmallVector<BasicBlockInfo, 16> BlockInfo;
std::unique_ptr<RegScavenger> RS;
+ LivePhysRegs LiveRegs;
MachineFunction *MF;
+ const TargetRegisterInfo *TRI;
const TargetInstrInfo *TII;
bool relaxBranchInstructions();
@@ -252,6 +255,10 @@
// All BBOffsets following these blocks must be modified.
adjustBlockOffsets(*OrigBB);
+ // Need to fix live-in lists if we track liveness.
+ if (TRI->trackLivenessAfterRegAlloc(*MF))
+ computeLiveIns(LiveRegs, *TRI, *NewBB);
+
++NumSplit;
return NewBB;
@@ -411,8 +418,9 @@
for (MachineFunction::iterator I = MF->begin(); I != MF->end(); ++I) {
MachineBasicBlock &MBB = *I;
- auto Last = MBB.rbegin();
- if (Last == MBB.rend()) // Empty block.
+ // Empty block?
+ MachineBasicBlock::iterator Last = MBB.getLastNonDebugInstr();
+ if (Last == MBB.end())
continue;
// Expand the unconditional branch first if necessary. If there is a
@@ -473,7 +481,7 @@
const TargetSubtargetInfo &ST = MF->getSubtarget();
TII = ST.getInstrInfo();
- const TargetRegisterInfo *TRI = ST.getRegisterInfo();
+ TRI = ST.getRegisterInfo();
if (TRI->trackLivenessAfterRegAlloc(*MF))
RS.reset(new RegScavenger());