Enable -split-phi-edges by default, except when -regalloc=local.

The local register allocator doesn't like it when LiveVariables is run.
We should also disable edge splitting under -O0, but that has to wait a bit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89125 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2009-11-17 19:15:50 +00:00
parent 464ecfee71
commit 95a2c8f1d0
3 changed files with 17 additions and 4 deletions

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@ -21,6 +21,7 @@
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegAllocRegistry.h"
#include "llvm/Function.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/ADT/SmallPtrSet.h"
@ -39,7 +40,7 @@ STATISTIC(NumSplits, "Number of critical edges split on demand");
static cl::opt<bool>
SplitEdges("split-phi-edges",
cl::desc("Split critical edges during phi elimination"),
cl::init(false), cl::Hidden);
cl::init(true), cl::Hidden);
char PHIElimination::ID = 0;
static RegisterPass<PHIElimination>
@ -47,10 +48,21 @@ X("phi-node-elimination", "Eliminate PHI nodes for register allocation");
const PassInfo *const llvm::PHIEliminationID = &X;
namespace llvm { FunctionPass *createLocalRegisterAllocator(); }
// Should we run edge splitting?
static bool shouldSplitEdges() {
// Edge splitting breaks the local register allocator. It cannot tolerate
// LiveVariables being run.
if (RegisterRegAlloc::getDefault() == createLocalRegisterAllocator)
return false;
return SplitEdges;
}
void llvm::PHIElimination::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addPreserved<LiveVariables>();
AU.addPreserved<MachineDominatorTree>();
if (SplitEdges) {
if (shouldSplitEdges()) {
AU.addRequired<LiveVariables>();
} else {
AU.setPreservesCFG();
@ -67,7 +79,7 @@ bool llvm::PHIElimination::runOnMachineFunction(MachineFunction &Fn) {
bool Changed = false;
// Split critical edges to help the coalescer
if (SplitEdges)
if (shouldSplitEdges())
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
Changed |= SplitPHIEdges(Fn, *I);

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@ -1,5 +1,6 @@
; RUN: llc < %s -mtriple=x86_64-apple-darwin
; RUN: llc < %s -mtriple=x86_64-apple-darwin -relocation-model=pic -disable-fp-elim -O0 -regalloc=local
; PR5534
%struct.CGPoint = type { double, double }
%struct.NSArray = type { %struct.NSObject }

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@ -1,6 +1,6 @@
; RUN: llc < %s -mtriple=x86_64-apple-darwin10 -relocation-model=pic -disable-fp-elim -color-ss-with-regs -stats -info-output-file - > %t
; RUN: grep stackcoloring %t | grep "stack slot refs replaced with reg refs" | grep 6
; RUN: grep asm-printer %t | grep 177
; RUN: grep asm-printer %t | grep 175
type { [62 x %struct.Bitvec*] } ; type %0
type { i8* } ; type %1