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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117332 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index 1ee27f0..ce3eda7 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -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;