Record CodeGen optimization level in the BranchFolding pass so that we can
use it to control tail merging when there is a tradeoff between performance
and code size. When there is only 1 instruction in the common tail, we have
been merging. That can be good for code size but is a definite loss for
performance. Now we will avoid tail merging in that case when the
optimization level is "Aggressive", i.e., "-O3". Radar 7338114.
Since the IfConversion pass invokes BranchFolding, it too needs to know
the optimization level. Note that I removed the RegisterPass instantiation
for IfConversion because it required a default constructor. If someone
wants to keep that for some reason, we can add a default constructor with
a hard-wired optimization level.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85346 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index 45f08b1..be9e1f1 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -148,9 +148,11 @@
const TargetInstrInfo *TII;
bool MadeChange;
int FnNum;
+ CodeGenOpt::Level OptLevel;
public:
static char ID;
- IfConverter() : MachineFunctionPass(&ID), FnNum(-1) {}
+ IfConverter(CodeGenOpt::Level OL) :
+ MachineFunctionPass(&ID), FnNum(-1), OptLevel(OL) {}
virtual bool runOnMachineFunction(MachineFunction &MF);
virtual const char *getPassName() const { return "If Converter"; }
@@ -219,10 +221,9 @@
char IfConverter::ID = 0;
}
-static RegisterPass<IfConverter>
-X("if-converter", "If Converter");
-
-FunctionPass *llvm::createIfConverterPass() { return new IfConverter(); }
+FunctionPass *llvm::createIfConverterPass(CodeGenOpt::Level OptLevel) {
+ return new IfConverter(OptLevel);
+}
bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
TLI = MF.getTarget().getTargetLowering();
@@ -362,7 +363,7 @@
BBAnalysis.clear();
if (MadeChange) {
- BranchFolder BF(false);
+ BranchFolder BF(false, OptLevel);
BF.OptimizeFunction(MF, TII,
MF.getTarget().getRegisterInfo(),
getAnalysisIfAvailable<MachineModuleInfo>());