Need to insert all moves due to PHI nodes before *ALL* jumps in a predecessor
basic block, as there could be multiple.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5016 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocSimple.cpp b/lib/CodeGen/RegAllocSimple.cpp
index 3a58b5a..6def3a1 100644
--- a/lib/CodeGen/RegAllocSimple.cpp
+++ b/lib/CodeGen/RegAllocSimple.cpp
@@ -92,21 +92,6 @@
regs = Desc.ImplicitDefs;
while (*regs)
RegsUsed[*regs++] = 1;
-
-
- /*
- for (int i = MI->getNumOperands() - 1; i >= 0; --i) {
- const MachineOperand &op = MI->getOperand(i);
- if (op.isMachineRegister())
- RegsUsed[op.getAllocatedRegNum()] = 1;
- }
-
- for (int i = MI->getNumImplicitRefs() - 1; i >= 0; --i) {
- const MachineOperand &op = MI->getImplicitOp(i);
- if (op.isMachineRegister())
- RegsUsed[op.getAllocatedRegNum()] = 1;
- }
- */
}
void cleanupAfterFunction() {
@@ -297,6 +282,16 @@
MachineBasicBlock::iterator opI = opBlock->end();
MachineInstr *opMI = *(--opI);
const MachineInstrInfo &MII = TM.getInstrInfo();
+ // must backtrack over ALL the branches in the previous block, until no more
+ while ((MII.isBranch(opMI->getOpcode()) || MII.isReturn(opMI->getOpcode()))
+ && opI != opBlock->begin())
+ {
+ opMI = *(--opI);
+ }
+ // move back to the first branch instruction so new instructions
+ // are inserted right in front of it and not in front of a non-branch
+ ++opI;
+
// insert the move just before the return/branch
if (MII.isReturn(opMI->getOpcode()) || MII.isBranch(opMI->getOpcode()))