Fix incorrect logic in maintaining the side-effect of compiler generated outliner functions
Summary: Fix incorrect logic in maintaining the side-effect of compiler generated outliner functions by adding the up-exposed uses.
Reviewers: paquette, tellenbach
Reviewed By: paquette
Subscribers: aemerson, lebedev.ri, hiraditya, llvm-commits, jinlin
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71217
diff --git a/llvm/lib/CodeGen/MachineOutliner.cpp b/llvm/lib/CodeGen/MachineOutliner.cpp
index 7081950..19bcb09 100644
--- a/llvm/lib/CodeGen/MachineOutliner.cpp
+++ b/llvm/lib/CodeGen/MachineOutliner.cpp
@@ -56,6 +56,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/MachineOutliner.h"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/Twine.h"
#include "llvm/CodeGen/MachineFunction.h"
@@ -1245,31 +1246,53 @@
// make sure that the ranges we yank things out of aren't wrong.
if (MBB.getParent()->getProperties().hasProperty(
MachineFunctionProperties::Property::TracksLiveness)) {
- // Helper lambda for adding implicit def operands to the call
+ // The following code is to add implicit def operands to the call
// instruction. It also updates call site information for moved
// code.
- auto CopyDefsAndUpdateCalls = [&CallInst](MachineInstr &MI) {
- for (MachineOperand &MOP : MI.operands()) {
- // Skip over anything that isn't a register.
- if (!MOP.isReg())
- continue;
-
- // If it's a def, add it to the call instruction.
- if (MOP.isDef())
- CallInst->addOperand(MachineOperand::CreateReg(
- MOP.getReg(), true, /* isDef = true */
- true /* isImp = true */));
- }
- if (MI.shouldUpdateCallSiteInfo())
- MI.getMF()->eraseCallSiteInfo(&MI);
- };
+ SmallSet<Register, 2> UseRegs, DefRegs;
// Copy over the defs in the outlined range.
// First inst in outlined range <-- Anything that's defined in this
// ... .. range has to be added as an
// implicit Last inst in outlined range <-- def to the call
// instruction. Also remove call site information for outlined block
- // of code.
- std::for_each(CallInst, std::next(EndIt), CopyDefsAndUpdateCalls);
+ // of code. The exposed uses need to be copied in the outlined range.
+ for (MachineBasicBlock::reverse_iterator Iter = EndIt.getReverse(),
+ Last = std::next(CallInst.getReverse());
+ Iter != Last; Iter++) {
+ MachineInstr *MI = &*Iter;
+ for (MachineOperand &MOP : MI->operands()) {
+ // Skip over anything that isn't a register.
+ if (!MOP.isReg())
+ continue;
+
+ if (MOP.isDef()) {
+ // Introduce DefRegs set to skip the redundant register.
+ DefRegs.insert(MOP.getReg());
+ if (UseRegs.count(MOP.getReg()))
+ // Since the regiester is modeled as defined,
+ // it is not necessary to be put in use register set.
+ UseRegs.erase(MOP.getReg());
+ } else if (!MOP.isUndef()) {
+ // Any register which is not undefined should
+ // be put in the use register set.
+ UseRegs.insert(MOP.getReg());
+ }
+ }
+ if (MI->isCandidateForCallSiteEntry())
+ MI->getMF()->eraseCallSiteInfo(MI);
+ }
+
+ for (const Register &I : DefRegs)
+ // If it's a def, add it to the call instruction.
+ CallInst->addOperand(MachineOperand::CreateReg(
+ I, true, /* isDef = true */
+ true /* isImp = true */));
+
+ for (const Register &I : UseRegs)
+ // If it's a exposed use, add it to the call instruction.
+ CallInst->addOperand(
+ MachineOperand::CreateReg(I, false, /* isDef = false */
+ true /* isImp = true */));
}
// Erase from the point after where the call was inserted up to, and