Teach if-converter to be more careful with predicating instructions that would
take multiple cycles to decode.
For the current if-converter clients (actually only ARM), the instructions that
are predicated on false are not nops. They would still take machine cycles to
decode. Micro-coded instructions such as LDM / STM can potentially take multiple
cycles to decode. If-converter should take treat them as non-micro-coded
simple instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113570 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index 0ea30d7..d73cd53 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -18,6 +18,7 @@
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetInstrItineraries.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
@@ -150,6 +151,7 @@
const TargetLowering *TLI;
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
+ const InstrItineraryData *InstrItins;
bool MadeChange;
int FnNum;
public:
@@ -238,6 +240,7 @@
TLI = MF.getTarget().getTargetLowering();
TII = MF.getTarget().getInstrInfo();
TRI = MF.getTarget().getRegisterInfo();
+ InstrItins = MF.getTarget().getInstrItineraryData();
if (!TII) return false;
// Tail merge tend to expose more if-conversion opportunities.
@@ -641,9 +644,10 @@
bool isCondBr = BBI.IsBrAnalyzable && TID.isConditionalBranch();
if (!isCondBr) {
- if (!isPredicated)
- BBI.NonPredSize++;
- else if (!AlreadyPredicated) {
+ if (!isPredicated) {
+ unsigned NumOps = TII->getNumMicroOps(&*I, InstrItins);
+ BBI.NonPredSize += NumOps;
+ } else if (!AlreadyPredicated) {
// FIXME: This instruction is already predicated before the
// if-conversion pass. It's probably something like a conditional move.
// Mark this block unpredicable for now.
@@ -1364,7 +1368,8 @@
MachineInstr *MI = MF.CloneMachineInstr(I);
ToBBI.BB->insert(ToBBI.BB->end(), MI);
- ToBBI.NonPredSize++;
+ unsigned NumOps = TII->getNumMicroOps(MI, InstrItins);
+ ToBBI.NonPredSize += NumOps;
if (!TII->isPredicated(I) && !MI->isDebugValue()) {
if (!TII->PredicateInstruction(MI, Cond)) {