[ImplicitNullChecks] Properly update the live-in of the block of the memory operation.
We basically replace:
HoistBB:
cond_br NullBB, NotNullBB
NullBB:
...
NotNullBB:
<reg> = load
into
HoistBB
<reg> = load_faulting_op NullBB
uncond_br NotNullBB
NullBB:
...
NotNullBB: ## <reg> is now live-in of NotNullBB
...
This partially fixes the machine verifier error for
test/CodeGen/X86/implicit-null-check.ll, but it still fails because
of the implicit CFG structure.
llvm-svn: 267817
diff --git a/llvm/lib/CodeGen/ImplicitNullChecks.cpp b/llvm/lib/CodeGen/ImplicitNullChecks.cpp
index 2c03f72..c923ddd 100644
--- a/llvm/lib/CodeGen/ImplicitNullChecks.cpp
+++ b/llvm/lib/CodeGen/ImplicitNullChecks.cpp
@@ -397,7 +397,16 @@
// check earlier ensures that this bit of code motion is legal. We do not
// touch the successors list for any basic block since we haven't changed
// control flow, we've just made it implicit.
- insertFaultingLoad(NC.MemOperation, NC.CheckBlock, HandlerLabel);
+ MachineInstr *FaultingLoad =
+ insertFaultingLoad(NC.MemOperation, NC.CheckBlock, HandlerLabel);
+ // Now the value of the MemOperation, if any, is live-in of block
+ // of MemOperation.
+ unsigned Reg = FaultingLoad->getOperand(0).getReg();
+ if (Reg) {
+ MachineBasicBlock *MBB = NC.MemOperation->getParent();
+ if (!MBB->isLiveIn(Reg))
+ MBB->addLiveIn(Reg);
+ }
NC.MemOperation->eraseFromParent();
NC.CheckOperation->eraseFromParent();