[llvm-commits] [llvm] r132483 - in /llvm/trunk: lib/CodeGen/ScheduleDAGInstrs.cpp lib/CodeGen/ScheduleDAGInstrs.h test/CodeGen/ARM/debug-info-branch-folding.ll
Devang Patel
dpatel at apple.com
Thu Jun 2 13:07:12 PDT 2011
Author: dpatel
Date: Thu Jun 2 15:07:12 2011
New Revision: 132483
URL: http://llvm.org/viewvc/llvm-project?rev=132483&view=rev
Log:
During post RA scheduling, do not try to chase reg defs. to preserve DBG_VALUEs. This approach has several downsides, for example, it does not work when dbg value is a constant integer, it does not work if reg is defined more than once, it places end of debug value range markers in the wrong place. It even causes misleading incorrect debug info when duplicate DBG_VALUE instructions point to same reg def.
Instead, use simpler approach and let DBG_VALUE follow its predecessor instruction. After live debug value analysis pass, all DBG_VALUE instruction are placed at the right place. Thanks Jakob for the hint!
Modified:
llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.cpp
llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.h
llvm/trunk/test/CodeGen/ARM/debug-info-branch-folding.ll
Modified: llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.cpp?rev=132483&r1=132482&r2=132483&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.cpp (original)
+++ llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.cpp Thu Jun 2 15:07:12 2011
@@ -35,8 +35,9 @@
const MachineDominatorTree &mdt)
: ScheduleDAG(mf), MLI(mli), MDT(mdt), MFI(mf.getFrameInfo()),
InstrItins(mf.getTarget().getInstrItineraryData()),
- Defs(TRI->getNumRegs()), Uses(TRI->getNumRegs()), LoopRegs(MLI, MDT) {
- DbgValueVec.clear();
+ Defs(TRI->getNumRegs()), Uses(TRI->getNumRegs()),
+ FirstDbgValue(0), LoopRegs(MLI, MDT) {
+ DbgValues.clear();
}
/// Run - perform scheduling.
@@ -200,11 +201,6 @@
std::map<const Value *, SUnit *> AliasMemDefs, NonAliasMemDefs;
std::map<const Value *, std::vector<SUnit *> > AliasMemUses, NonAliasMemUses;
- // Keep track of dangling debug references to registers.
- std::vector<std::pair<MachineInstr*, unsigned> >
- DanglingDebugValue(TRI->getNumRegs(),
- std::make_pair(static_cast<MachineInstr*>(0), 0));
-
// Check to see if the scheduler cares about latencies.
bool UnitLatencies = ForceUnitLatencies();
@@ -214,7 +210,8 @@
// Remove any stale debug info; sometimes BuildSchedGraph is called again
// without emitting the info from the previous call.
- DbgValueVec.clear();
+ DbgValues.clear();
+ FirstDbgValue = NULL;
// Model data dependencies between instructions being scheduled and the
// ExitSU.
@@ -225,19 +222,20 @@
}
// Walk the list of instructions, from bottom moving up.
+ MachineInstr *PrevMI = NULL;
for (MachineBasicBlock::iterator MII = InsertPos, MIE = Begin;
MII != MIE; --MII) {
MachineInstr *MI = prior(MII);
- // DBG_VALUE does not have SUnit's built, so just remember these for later
- // reinsertion.
+ if (MI && PrevMI) {
+ DbgValues.push_back(std::make_pair(PrevMI, MI));
+ PrevMI = NULL;
+ }
+
if (MI->isDebugValue()) {
- if (MI->getNumOperands()==3 && MI->getOperand(0).isReg() &&
- MI->getOperand(0).getReg())
- DanglingDebugValue[MI->getOperand(0).getReg()] =
- std::make_pair(MI, DbgValueVec.size());
- DbgValueVec.push_back(MI);
+ PrevMI = MI;
continue;
}
+
const TargetInstrDesc &TID = MI->getDesc();
assert(!TID.isTerminator() && !MI->isLabel() &&
"Cannot schedule terminators or labels!");
@@ -261,12 +259,6 @@
assert(TRI->isPhysicalRegister(Reg) && "Virtual register encountered!");
- if (MO.isDef() && DanglingDebugValue[Reg].first!=0) {
- SU->DbgInstrList.push_back(DanglingDebugValue[Reg].first);
- DbgValueVec[DanglingDebugValue[Reg].second] = 0;
- DanglingDebugValue[Reg] = std::make_pair((MachineInstr*)0, 0);
- }
-
std::vector<SUnit *> &UseList = Uses[Reg];
// Defs are push in the order they are visited and never reordered.
std::vector<SUnit *> &DefList = Defs[Reg];
@@ -561,6 +553,8 @@
}
}
}
+ if (PrevMI)
+ FirstDbgValue = PrevMI;
for (int i = 0, e = TRI->getNumRegs(); i != e; ++i) {
Defs[i].clear();
@@ -670,13 +664,9 @@
BB->remove(I);
}
- // First reinsert any remaining debug_values; these are either constants,
- // or refer to live-in registers. The beginning of the block is the right
- // place for the latter. The former might reasonably be placed elsewhere
- // using some kind of ordering algorithm, but right now it doesn't matter.
- for (int i = DbgValueVec.size()-1; i>=0; --i)
- if (DbgValueVec[i])
- BB->insert(InsertPos, DbgValueVec[i]);
+ // If first instruction was a DBG_VALUE then put it back.
+ if (FirstDbgValue)
+ BB->insert(InsertPos, FirstDbgValue);
// Then re-insert them according to the given schedule.
for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
@@ -694,15 +684,18 @@
// Update the Begin iterator, as the first instruction in the block
// may have been scheduled later.
- if (!DbgValueVec.empty()) {
- for (int i = DbgValueVec.size()-1; i>=0; --i)
- if (DbgValueVec[i]!=0) {
- Begin = DbgValueVec[DbgValueVec.size()-1];
- break;
- }
- } else if (!Sequence.empty())
+ if (!Sequence.empty())
Begin = Sequence[0]->getInstr();
- DbgValueVec.clear();
+ // Reinsert any remaining debug_values.
+ for (std::vector<std::pair<MachineInstr *, MachineInstr *> >::iterator
+ DI = DbgValues.end(), DE = DbgValues.begin(); DI != DE; --DI) {
+ std::pair<MachineInstr *, MachineInstr *> P = *prior(DI);
+ MachineInstr *DbgValue = P.first;
+ MachineInstr *OrigPrivMI = P.second;
+ BB->insertAfter(OrigPrivMI, DbgValue);
+ }
+ DbgValues.clear();
+ FirstDbgValue = NULL;
return BB;
}
Modified: llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.h?rev=132483&r1=132482&r2=132483&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.h (original)
+++ llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.h Thu Jun 2 15:07:12 2011
@@ -110,9 +110,9 @@
std::vector<std::vector<SUnit *> > Defs;
std::vector<std::vector<SUnit *> > Uses;
- /// DbgValueVec - Remember DBG_VALUEs that refer to a particular
- /// register.
- std::vector<MachineInstr *>DbgValueVec;
+ /// DbgValues - Remember instruction that preceeds DBG_VALUE.
+ std::vector<std::pair<MachineInstr *, MachineInstr *> >DbgValues;
+ MachineInstr *FirstDbgValue;
/// PendingLoads - Remember where unknown loads are after the most recent
/// unknown store, as we iterate. As with Defs and Uses, this is here
Modified: llvm/trunk/test/CodeGen/ARM/debug-info-branch-folding.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/debug-info-branch-folding.ll?rev=132483&r1=132482&r2=132483&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/debug-info-branch-folding.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/debug-info-branch-folding.ll Thu Jun 2 15:07:12 2011
@@ -2,9 +2,11 @@
target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:32-f32:32:32-f64:32:32-v64:32:64-v128:32:128-a0:0:32-n32"
target triple = "thumbv7-apple-macosx10.6.7"
-;CHECK: Ltmp1:
-;CHECK-NEXT: @DEBUG_VALUE: x <- Q4+0
-;CHECK-NEXT: adr r0, #LCPI0_0
+;CHECK: vadd.f32 q4, q8, q8
+;CHECK-NEXT: Ltmp
+;CHECK-NEXT: @DEBUG_VALUE: y <- Q4+0
+;CHECK-NEXT: @DEBUG_VALUE: x <- Q4+0
+
@.str = external constant [13 x i8]
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