[llvm-commits] [llvm] r117332 - /llvm/trunk/lib/CodeGen/IfConversion.cpp
Bob Wilson
bob.wilson at apple.com
Mon Oct 25 17:02:21 PDT 2010
Author: bwilson
Date: Mon Oct 25 19:02:21 2010
New Revision: 117332
URL: http://llvm.org/viewvc/llvm-project?rev=117332&view=rev
Log:
Change if-conversion to keep track of the extra cost due to microcoded
instructions separately from the count of non-predicated instructions. The
instruction count is used in places to determine how many instructions to
copy, predicate, etc. and things get confused if that count includes the
extra cost for microcoded ops.
Modified:
llvm/trunk/lib/CodeGen/IfConversion.cpp
Modified: llvm/trunk/lib/CodeGen/IfConversion.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/IfConversion.cpp?rev=117332&r1=117331&r2=117332&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/IfConversion.cpp (original)
+++ llvm/trunk/lib/CodeGen/IfConversion.cpp Mon Oct 25 19:02:21 2010
@@ -93,6 +93,7 @@
/// ClobbersPred - True if BB could modify predicates (e.g. has
/// cmp, call, etc.)
/// NonPredSize - Number of non-predicated instructions.
+ /// ExtraCost - Extra cost for microcoded instructions.
/// BB - Corresponding MachineBasicBlock.
/// TrueBB / FalseBB- See AnalyzeBranch().
/// BrCond - Conditions for end of block conditional branches.
@@ -108,6 +109,7 @@
bool CannotBeCopied : 1;
bool ClobbersPred : 1;
unsigned NonPredSize;
+ unsigned ExtraCost;
MachineBasicBlock *BB;
MachineBasicBlock *TrueBB;
MachineBasicBlock *FalseBB;
@@ -117,7 +119,7 @@
IsAnalyzed(false), IsEnqueued(false), IsBrAnalyzable(false),
HasFallThrough(false), IsUnpredicable(false),
CannotBeCopied(false), ClobbersPred(false), NonPredSize(0),
- BB(0), TrueBB(0), FalseBB(0) {}
+ ExtraCost(0), BB(0), TrueBB(0), FalseBB(0) {}
};
/// IfcvtToken - Record information about pending if-conversions to attempt:
@@ -652,6 +654,7 @@
// Then scan all the instructions.
BBI.NonPredSize = 0;
+ BBI.ExtraCost = 0;
BBI.ClobbersPred = false;
for (MachineBasicBlock::iterator I = BBI.BB->begin(), E = BBI.BB->end();
I != E; ++I) {
@@ -667,8 +670,10 @@
if (!isCondBr) {
if (!isPredicated) {
+ BBI.NonPredSize++;
unsigned NumOps = TII->getNumMicroOps(&*I, InstrItins);
- BBI.NonPredSize += NumOps;
+ if (NumOps > 1)
+ BBI.ExtraCost += NumOps-1;
} else if (!AlreadyPredicated) {
// FIXME: This instruction is already predicated before the
// if-conversion pass. It's probably something like a conditional move.
@@ -815,8 +820,10 @@
}
if (CanRevCond && ValidDiamond(TrueBBI, FalseBBI, Dups, Dups2) &&
- MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize - (Dups + Dups2),
- *FalseBBI.BB, FalseBBI.NonPredSize - (Dups + Dups2),
+ MeetIfcvtSizeLimit(*TrueBBI.BB, (TrueBBI.NonPredSize - (Dups + Dups2) +
+ TrueBBI.ExtraCost),
+ *FalseBBI.BB, (FalseBBI.NonPredSize - (Dups + Dups2) +
+ FalseBBI.ExtraCost),
Prediction, Confidence) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond) &&
FeasibilityAnalysis(FalseBBI, RevCond)) {
@@ -834,7 +841,7 @@
}
if (ValidTriangle(TrueBBI, FalseBBI, false, Dups, Prediction, Confidence) &&
- MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize,
+ MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize + TrueBBI.ExtraCost,
Prediction, Confidence) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond, true)) {
// Triangle:
@@ -849,7 +856,7 @@
}
if (ValidTriangle(TrueBBI, FalseBBI, true, Dups, Prediction, Confidence) &&
- MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize,
+ MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize + TrueBBI.ExtraCost,
Prediction, Confidence) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond, true, true)) {
Tokens.push_back(new IfcvtToken(BBI, ICTriangleRev, TNeedSub, Dups));
@@ -857,7 +864,7 @@
}
if (ValidSimple(TrueBBI, Dups, Prediction, Confidence) &&
- MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize,
+ MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize + TrueBBI.ExtraCost,
Prediction, Confidence) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond)) {
// Simple (split, no rejoin):
@@ -875,7 +882,8 @@
// Try the other path...
if (ValidTriangle(FalseBBI, TrueBBI, false, Dups,
1.0-Prediction, Confidence) &&
- MeetIfcvtSizeLimit(*FalseBBI.BB, FalseBBI.NonPredSize,
+ MeetIfcvtSizeLimit(*FalseBBI.BB,
+ FalseBBI.NonPredSize + FalseBBI.ExtraCost,
1.0-Prediction, Confidence) &&
FeasibilityAnalysis(FalseBBI, RevCond, true)) {
Tokens.push_back(new IfcvtToken(BBI, ICTriangleFalse, FNeedSub, Dups));
@@ -884,7 +892,8 @@
if (ValidTriangle(FalseBBI, TrueBBI, true, Dups,
1.0-Prediction, Confidence) &&
- MeetIfcvtSizeLimit(*FalseBBI.BB, FalseBBI.NonPredSize,
+ MeetIfcvtSizeLimit(*FalseBBI.BB,
+ FalseBBI.NonPredSize + FalseBBI.ExtraCost,
1.0-Prediction, Confidence) &&
FeasibilityAnalysis(FalseBBI, RevCond, true, true)) {
Tokens.push_back(new IfcvtToken(BBI, ICTriangleFRev, FNeedSub, Dups));
@@ -892,7 +901,8 @@
}
if (ValidSimple(FalseBBI, Dups, 1.0-Prediction, Confidence) &&
- MeetIfcvtSizeLimit(*FalseBBI.BB, FalseBBI.NonPredSize,
+ MeetIfcvtSizeLimit(*FalseBBI.BB,
+ FalseBBI.NonPredSize + FalseBBI.ExtraCost,
1.0-Prediction, Confidence) &&
FeasibilityAnalysis(FalseBBI, RevCond)) {
Tokens.push_back(new IfcvtToken(BBI, ICSimpleFalse, FNeedSub, Dups));
@@ -1422,8 +1432,10 @@
MachineInstr *MI = MF.CloneMachineInstr(I);
ToBBI.BB->insert(ToBBI.BB->end(), MI);
+ ToBBI.NonPredSize++;
unsigned NumOps = TII->getNumMicroOps(MI, InstrItins);
- ToBBI.NonPredSize += NumOps;
+ if (NumOps > 1)
+ ToBBI.ExtraCost += NumOps-1;
if (!TII->isPredicated(I) && !MI->isDebugValue()) {
if (!TII->PredicateInstruction(MI, Cond)) {
@@ -1497,7 +1509,9 @@
FromBBI.Predicate.clear();
ToBBI.NonPredSize += FromBBI.NonPredSize;
+ ToBBI.ExtraCost += FromBBI.ExtraCost;
FromBBI.NonPredSize = 0;
+ FromBBI.ExtraCost = 0;
ToBBI.ClobbersPred |= FromBBI.ClobbersPred;
ToBBI.HasFallThrough = FromBBI.HasFallThrough;
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