[globalisel][combine] Split existing rules into a match and apply step
Summary:
The declarative tablegen definitions split rules into match and apply steps.
Prepare for that by doing the same in the C++ implementations. This aids
some of the migration effort while the tablegen version is incomplete.
Reviewers: bogner, volkan, aditya_nandakumar, paquette, aemerson
Reviewed By: aditya_nandakumar
Subscribers: rovka, kristof.beyls, Petar.Avramovic, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58150
llvm-svn: 353996
diff --git a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
index a2b1e8e..2eab574 100644
--- a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
@@ -46,6 +46,13 @@
}
bool CombinerHelper::tryCombineCopy(MachineInstr &MI) {
+ if (matchCombineCopy(MI)) {
+ applyCombineCopy(MI);
+ return true;
+ }
+ return false;
+}
+bool CombinerHelper::matchCombineCopy(MachineInstr &MI) {
if (MI.getOpcode() != TargetOpcode::COPY)
return false;
unsigned DstReg = MI.getOperand(0).getReg();
@@ -54,20 +61,18 @@
LLT SrcTy = MRI.getType(SrcReg);
// Simple Copy Propagation.
// a(sx) = COPY b(sx) -> Replace all uses of a with b.
- if (DstTy.isValid() && SrcTy.isValid() && DstTy == SrcTy) {
- MI.eraseFromParent();
- replaceRegWith(MRI, DstReg, SrcReg);
+ if (DstTy.isValid() && SrcTy.isValid() && DstTy == SrcTy)
return true;
- }
return false;
}
+void CombinerHelper::applyCombineCopy(MachineInstr &MI) {
+ unsigned DstReg = MI.getOperand(0).getReg();
+ unsigned SrcReg = MI.getOperand(1).getReg();
+ MI.eraseFromParent();
+ replaceRegWith(MRI, DstReg, SrcReg);
+}
namespace {
-struct PreferredTuple {
- LLT Ty; // The result type of the extend.
- unsigned ExtendOpcode; // G_ANYEXT/G_SEXT/G_ZEXT
- MachineInstr *MI;
-};
/// Select a preference between two uses. CurrentUse is the current preference
/// while *ForCandidate is attributes of the candidate under consideration.
@@ -152,16 +157,16 @@
} // end anonymous namespace
bool CombinerHelper::tryCombineExtendingLoads(MachineInstr &MI) {
- struct InsertionPoint {
- MachineOperand *UseMO;
- MachineBasicBlock *InsertIntoBB;
- MachineBasicBlock::iterator InsertBefore;
- InsertionPoint(MachineOperand *UseMO, MachineBasicBlock *InsertIntoBB,
- MachineBasicBlock::iterator InsertBefore)
- : UseMO(UseMO), InsertIntoBB(InsertIntoBB), InsertBefore(InsertBefore) {
- }
- };
+ PreferredTuple Preferred;
+ if (matchCombineExtendingLoads(MI, Preferred)) {
+ applyCombineExtendingLoads(MI, Preferred);
+ return true;
+ }
+ return false;
+}
+bool CombinerHelper::matchCombineExtendingLoads(MachineInstr &MI,
+ PreferredTuple &Preferred) {
// We match the loads and follow the uses to the extend instead of matching
// the extends and following the def to the load. This is because the load
// must remain in the same position for correctness (unless we also add code
@@ -199,7 +204,7 @@
: MI.getOpcode() == TargetOpcode::G_SEXTLOAD
? TargetOpcode::G_SEXT
: TargetOpcode::G_ZEXT;
- PreferredTuple Preferred = {LLT(), PreferredOpcode, nullptr};
+ Preferred = {LLT(), PreferredOpcode, nullptr};
for (auto &UseMI : MRI.use_instructions(LoadValue.getReg())) {
if (UseMI.getOpcode() == TargetOpcode::G_SEXT ||
UseMI.getOpcode() == TargetOpcode::G_ZEXT ||
@@ -218,6 +223,20 @@
assert(Preferred.Ty != LoadValueTy && "Extending to same type?");
LLVM_DEBUG(dbgs() << "Preferred use is: " << *Preferred.MI);
+ return true;
+}
+
+void CombinerHelper::applyCombineExtendingLoads(MachineInstr &MI,
+ PreferredTuple &Preferred) {
+ struct InsertionPoint {
+ MachineOperand *UseMO;
+ MachineBasicBlock *InsertIntoBB;
+ MachineBasicBlock::iterator InsertBefore;
+ InsertionPoint(MachineOperand *UseMO, MachineBasicBlock *InsertIntoBB,
+ MachineBasicBlock::iterator InsertBefore)
+ : UseMO(UseMO), InsertIntoBB(InsertIntoBB), InsertBefore(InsertBefore) {
+ }
+ };
// Rewrite the load to the chosen extending load.
unsigned ChosenDstReg = Preferred.MI->getOperand(0).getReg();
@@ -232,6 +251,7 @@
// Rewrite all the uses to fix up the types.
SmallVector<MachineInstr *, 1> ScheduleForErase;
SmallVector<InsertionPoint, 4> ScheduleForInsert;
+ auto &LoadValue = MI.getOperand(0);
for (auto &UseMO : MRI.use_operands(LoadValue.getReg())) {
MachineInstr *UseMI = UseMO.getParent();
@@ -331,8 +351,6 @@
}
MI.getOperand(0).setReg(ChosenDstReg);
Observer.changedInstr(MI);
-
- return true;
}
bool CombinerHelper::tryCombine(MachineInstr &MI) {