[llvm-commits] [llvm] r85799 - in /llvm/trunk: lib/CodeGen/MachineLICM.cpp test/CodeGen/ARM/remat.ll test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll
Evan Cheng
evan.cheng at apple.com
Mon Nov 2 00:09:50 PST 2009
Author: evancheng
Date: Mon Nov 2 02:09:49 2009
New Revision: 85799
URL: http://llvm.org/viewvc/llvm-project?rev=85799&view=rev
Log:
Initilize the machine LICM CSE map upon the first time an instruction is hoisted to
the loop preheader. Add instructions which are already in the preheader block that
may be common expressions of those that are hoisted out. These does get a few more
instructions CSE'ed.
Modified:
llvm/trunk/lib/CodeGen/MachineLICM.cpp
llvm/trunk/test/CodeGen/ARM/remat.ll
llvm/trunk/test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll
Modified: llvm/trunk/lib/CodeGen/MachineLICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineLICM.cpp?rev=85799&r1=85798&r2=85799&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineLICM.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineLICM.cpp Mon Nov 2 02:09:49 2009
@@ -56,12 +56,12 @@
// State that is updated as we process loops
bool Changed; // True if a loop is changed.
+ bool FirstInLoop; // True if it's the first LICM in the loop.
MachineLoop *CurLoop; // The current loop we are working on.
MachineBasicBlock *CurPreheader; // The preheader for CurLoop.
- // For each BB and opcode pair, keep a list of hoisted instructions.
- DenseMap<std::pair<unsigned, unsigned>,
- std::vector<const MachineInstr*> > CSEMap;
+ // For each opcode, keep a list of potentail CSE instructions.
+ DenseMap<unsigned, std::vector<const MachineInstr*> > CSEMap;
public:
static char ID; // Pass identification, replacement for typeid
MachineLICM() : MachineFunctionPass(&ID) {}
@@ -115,6 +115,11 @@
/// that is safe to hoist, this instruction is called to do the dirty work.
///
void Hoist(MachineInstr *MI);
+
+ /// InitCSEMap - Initialize the CSE map with instructions that are in the
+ /// current loop preheader that may become duplicates of instructions that
+ /// are hoisted out of the loop.
+ void InitCSEMap(MachineBasicBlock *BB);
};
} // end anonymous namespace
@@ -140,7 +145,7 @@
bool MachineLICM::runOnMachineFunction(MachineFunction &MF) {
DEBUG(errs() << "******** Machine LICM ********\n");
- Changed = false;
+ Changed = FirstInLoop = false;
TM = &MF.getTarget();
TII = TM->getInstrInfo();
TRI = TM->getRegisterInfo();
@@ -152,8 +157,7 @@
DT = &getAnalysis<MachineDominatorTree>();
AA = &getAnalysis<AliasAnalysis>();
- for (MachineLoopInfo::iterator
- I = LI->begin(), E = LI->end(); I != E; ++I) {
+ for (MachineLoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I) {
CurLoop = *I;
// Only visit outer-most preheader-sporting loops.
@@ -170,7 +174,11 @@
if (!CurPreheader)
continue;
+ // CSEMap is initialized for loop header when the first instruction is
+ // being hoisted.
+ FirstInLoop = true;
HoistRegion(DT->getNode(CurLoop->getHeader()));
+ CSEMap.clear();
}
return Changed;
@@ -191,10 +199,7 @@
for (MachineBasicBlock::iterator
MII = BB->begin(), E = BB->end(); MII != E; ) {
MachineBasicBlock::iterator NextMII = MII; ++NextMII;
- MachineInstr &MI = *MII;
-
- Hoist(&MI);
-
+ Hoist(&*MII);
MII = NextMII;
}
@@ -430,6 +435,27 @@
return NewMIs[0];
}
+void MachineLICM::InitCSEMap(MachineBasicBlock *BB) {
+ for (MachineBasicBlock::iterator I = BB->begin(),E = BB->end(); I != E; ++I) {
+ const MachineInstr *MI = &*I;
+ // FIXME: For now, only hoist re-materilizable instructions. LICM will
+ // increase register pressure. We want to make sure it doesn't increase
+ // spilling.
+ if (TII->isTriviallyReMaterializable(MI, AA)) {
+ unsigned Opcode = MI->getOpcode();
+ DenseMap<unsigned, std::vector<const MachineInstr*> >::iterator
+ CI = CSEMap.find(Opcode);
+ if (CI != CSEMap.end())
+ CI->second.push_back(MI);
+ else {
+ std::vector<const MachineInstr*> CSEMIs;
+ CSEMIs.push_back(MI);
+ CSEMap.insert(std::make_pair(Opcode, CSEMIs));
+ }
+ }
+ }
+}
+
/// Hoist - When an instruction is found to use only loop invariant operands
/// that are safe to hoist, this instruction is called to do the dirty work.
///
@@ -454,11 +480,14 @@
errs() << "\n";
});
+ // If this is the first instruction being hoisted to the preheader,
+ // initialize the CSE map with potential common expressions.
+ InitCSEMap(CurPreheader);
+
// Look for opportunity to CSE the hoisted instruction.
- std::pair<unsigned, unsigned> BBOpcPair =
- std::make_pair(CurPreheader->getNumber(), MI->getOpcode());
- DenseMap<std::pair<unsigned, unsigned>,
- std::vector<const MachineInstr*> >::iterator CI = CSEMap.find(BBOpcPair);
+ unsigned Opcode = MI->getOpcode();
+ DenseMap<unsigned, std::vector<const MachineInstr*> >::iterator
+ CI = CSEMap.find(Opcode);
bool DoneCSE = false;
if (CI != CSEMap.end()) {
const MachineInstr *Dup = LookForDuplicate(MI, CI->second, RegInfo);
@@ -477,15 +506,15 @@
// Otherwise, splice the instruction to the preheader.
if (!DoneCSE) {
- CurPreheader->splice(CurPreheader->getFirstTerminator(),
- MI->getParent(), MI);
+ CurPreheader->splice(CurPreheader->getFirstTerminator(),MI->getParent(),MI);
+
// Add to the CSE map.
if (CI != CSEMap.end())
CI->second.push_back(MI);
else {
std::vector<const MachineInstr*> CSEMIs;
CSEMIs.push_back(MI);
- CSEMap.insert(std::make_pair(BBOpcPair, CSEMIs));
+ CSEMap.insert(std::make_pair(Opcode, CSEMIs));
}
}
Modified: llvm/trunk/test/CodeGen/ARM/remat.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/remat.ll?rev=85799&r1=85798&r2=85799&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/remat.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/remat.ll Mon Nov 2 02:09:49 2009
@@ -1,5 +1,5 @@
; RUN: llc < %s -mtriple=arm-apple-darwin
-; RUN: llc < %s -mtriple=arm-apple-darwin -stats -info-output-file - | grep "Number of re-materialization" | grep 4
+; RUN: llc < %s -mtriple=arm-apple-darwin -stats -info-output-file - | grep "Number of re-materialization" | grep 5
%struct.CONTENTBOX = type { i32, i32, i32, i32, i32 }
%struct.LOCBOX = type { i32, i32, i32, i32 }
Modified: llvm/trunk/test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll?rev=85799&r1=85798&r2=85799&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll (original)
+++ llvm/trunk/test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll Mon Nov 2 02:09:49 2009
@@ -1,6 +1,5 @@
-; RUN: llc < %s -march=x86 -mattr=+sse2 -stats |& \
-; RUN: grep {1 .*folded into instructions}
-; Increment in loop bb.128.i adjusted to 2, to prevent loop reversal from
+; RUN: llc < %s -march=x86 -mattr=+sse2 | FileCheck %s
+; Increment in loop bb.i28.i adjusted to 2, to prevent loop reversal from
; kicking in.
declare fastcc void @rdft(i32, i32, double*, i32*, double*)
@@ -34,6 +33,9 @@
br label %bb.i28.i
bb.i28.i: ; preds = %bb.i28.i, %cond_next36.i
+; CHECK: %bb.i28.i
+; CHECK: addl $2
+; CHECK: addl $2
%j.0.reg2mem.0.i16.i = phi i32 [ 0, %cond_next36.i ], [ %indvar.next39.i, %bb.i28.i ] ; <i32> [#uses=2]
%din_addr.1.reg2mem.0.i17.i = phi double [ 0.000000e+00, %cond_next36.i ], [ %tmp16.i25.i, %bb.i28.i ] ; <double> [#uses=1]
%tmp1.i18.i = fptosi double %din_addr.1.reg2mem.0.i17.i to i32 ; <i32> [#uses=2]
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