Changes in directory llvm/lib/CodeGen:
IfConversion.cpp updated: 1.53 -> 1.54
---
Log message:
Not every predicable block can be safely duplicated.
---
Diffs of the changes: (+35 -8)
IfConversion.cpp | 43 +++++++++++++++++++++++++++++++++++--------
1 files changed, 35 insertions(+), 8 deletions(-)
Index: llvm/lib/CodeGen/IfConversion.cpp
diff -u llvm/lib/CodeGen/IfConversion.cpp:1.53
llvm/lib/CodeGen/IfConversion.cpp:1.54
--- llvm/lib/CodeGen/IfConversion.cpp:1.53 Fri Jun 15 14:06:07 2007
+++ llvm/lib/CodeGen/IfConversion.cpp Fri Jun 15 16:18:05 2007
@@ -100,6 +100,7 @@
bool IsBrAnalyzable : 1;
bool HasFallThrough : 1;
bool IsUnpredicable : 1;
+ bool CannotBeCopied : 1;
bool ClobbersPred : 1;
unsigned NonPredSize;
MachineBasicBlock *BB;
@@ -111,7 +112,7 @@
BBInfo() : Kind(ICNotClassfied), IsDone(false), IsBeingAnalyzed(false),
IsAnalyzed(false), IsEnqueued(false), IsBrAnalyzable(false),
HasFallThrough(false), IsUnpredicable(false),
- ClobbersPred(false), NonPredSize(0),
+ CannotBeCopied(false), ClobbersPred(false), NonPredSize(0),
BB(0), TrueBB(0), FalseBB(0), TailBB(0) {}
};
@@ -334,8 +335,9 @@
if (TrueBBI.IsBeingAnalyzed)
return false;
- if (TrueBBI.BB->pred_size() != 1) {
- if (TrueBBI.NonPredSize > TLI->getIfCvtDupBlockSizeLimit())
+ if (TrueBBI.BB->pred_size() > 1) {
+ if (TrueBBI.CannotBeCopied ||
+ TrueBBI.NonPredSize > TLI->getIfCvtDupBlockSizeLimit())
return false;
}
@@ -349,7 +351,10 @@
if (TrueBBI.IsBeingAnalyzed)
return false;
- if (TrueBBI.BB->pred_size() != 1) {
+ if (TrueBBI.BB->pred_size() > 1) {
+ if (TrueBBI.CannotBeCopied)
+ return false;
+
unsigned Size = TrueBBI.NonPredSize;
if (TrueBBI.FalseBB)
++Size;
@@ -420,6 +425,9 @@
bool SeenCondBr = false;
for (MachineBasicBlock::iterator I = BBI.BB->begin(), E = BBI.BB->end();
I != E; ++I) {
+ if (!BBI.CannotBeCopied && !TII->CanBeDuplicated(I))
+ BBI.CannotBeCopied = true;
+
const TargetInstrDescriptor *TID = I->getInstrDescriptor();
bool isPredicated = TII->isPredicated(I);
bool isCondBr = BBI.IsBrAnalyzable &&
@@ -721,11 +729,20 @@
BBInfo *NextBBI = &FalseBBI;
std::vector<MachineOperand> Cond(BBI.BrCond);
- if (BBI.Kind == ICSimpleFalse) {
+ if (BBI.Kind == ICSimpleFalse)
std::swap(CvtBBI, NextBBI);
- TII->ReverseBranchCondition(Cond);
+
+ if (CvtBBI->CannotBeCopied && CvtBBI->BB->pred_size() > 1) {
+ // Something has changed. It's no longer safe to predicate this block.
+ BBI.Kind = ICNotClassfied;
+ BBI.IsAnalyzed = false;
+ CvtBBI->IsAnalyzed = false;
+ return false;
}
+ if (BBI.Kind == ICSimpleFalse)
+ TII->ReverseBranchCondition(Cond);
+
if (CvtBBI->BB->pred_size() > 1) {
BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB);
// Copy instructions in the true block, predicate them add them to
@@ -777,10 +794,20 @@
BBInfo *NextBBI = &FalseBBI;
std::vector<MachineOperand> Cond(BBI.BrCond);
- if (BBI.Kind == ICTriangleFalse || BBI.Kind == ICTriangleFRev) {
+ if (BBI.Kind == ICTriangleFalse || BBI.Kind == ICTriangleFRev)
std::swap(CvtBBI, NextBBI);
- TII->ReverseBranchCondition(Cond);
+
+ if (CvtBBI->CannotBeCopied && CvtBBI->BB->pred_size() > 1) {
+ // Something has changed. It's no longer safe to predicate this block.
+ BBI.Kind = ICNotClassfied;
+ BBI.IsAnalyzed = false;
+ CvtBBI->IsAnalyzed = false;
+ return false;
}
+
+ if (BBI.Kind == ICTriangleFalse || BBI.Kind == ICTriangleFRev)
+ TII->ReverseBranchCondition(Cond);
+
if (BBI.Kind == ICTriangleRev || BBI.Kind == ICTriangleFRev) {
ReverseBranchCondition(*CvtBBI);
// BB has been changed, modify its predecessors (except for this
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