[llvm-commits] CVS: llvm/lib/CodeGen/IfConversion.cpp
Evan Cheng
evan.cheng at apple.com
Thu May 17 18:56:18 PDT 2007
Changes in directory llvm/lib/CodeGen:
IfConversion.cpp updated: 1.5 -> 1.6
---
Log message:
If true / false blocks fallthrough before ifcvt, add unconditional branches to ifcvt'd block.
---
Diffs of the changes: (+19 -4)
IfConversion.cpp | 23 +++++++++++++++++++----
1 files changed, 19 insertions(+), 4 deletions(-)
Index: llvm/lib/CodeGen/IfConversion.cpp
diff -u llvm/lib/CodeGen/IfConversion.cpp:1.5 llvm/lib/CodeGen/IfConversion.cpp:1.6
--- llvm/lib/CodeGen/IfConversion.cpp:1.5 Thu May 17 19:20:58 2007
+++ llvm/lib/CodeGen/IfConversion.cpp Thu May 17 20:55:58 2007
@@ -87,8 +87,6 @@
TII = MF.getTarget().getInstrInfo();
if (!TII) return false;
- MadeChange = false;
-
MF.RenumberBlocks();
unsigned NumBBs = MF.getNumBlockIDs();
BBAnalysis.resize(NumBBs);
@@ -98,6 +96,7 @@
// candidates to perform if-convesion.
InitialFunctionAnalysis(MF, Candidates);
+ MadeChange = false;
for (unsigned i = 0, e = Candidates.size(); i != e; ++i) {
BBInfo &BBI = BBAnalysis[Candidates[i]];
switch (BBI.Kind) {
@@ -111,6 +110,9 @@
break;
}
}
+
+ BBAnalysis.clear();
+
return MadeChange;
}
@@ -150,6 +152,10 @@
if (TrueBBI.Kind != ICNotClassfied)
return;
+ // TODO: Only handle very simple cases for now.
+ if (TrueBBI.FalseBB || TrueBBI.Cond.size())
+ return;
+
// No false branch. This BB must end with a conditional branch and a
// fallthrough.
if (!BBI.FalseBB)
@@ -168,8 +174,7 @@
return;
// TODO: Only handle very simple cases for now.
- if (TrueBBI.FalseBB || FalseBBI.FalseBB ||
- TrueBBI.Cond.size() || FalseBBI.Cond.size())
+ if (FalseBBI.FalseBB || FalseBBI.Cond.size())
return;
if (TrueBBI.TrueBB && TrueBBI.TrueBB == BBI.FalseBB) {
@@ -309,11 +314,21 @@
TrueBBI.Size -= TII->RemoveBranch(*BBI.TrueBB);
PredicateBlock(BBI.TrueBB, BBI.Cond);
+ // Either the 'true' block fallthrough to another block or it ends with a
+ // return. If it's the former, add a conditional branch to its successor.
+ if (!TrueBBI.TrueBB)
+ TII->InsertBranch(*BBI.TrueBB, *BBI.TrueBB->succ_begin(), NULL, BBI.Cond);
+
// Predicate the 'false' block.
std::vector<MachineOperand> NewCond(BBI.Cond);
TII->ReverseBranchCondition(NewCond);
PredicateBlock(BBI.FalseBB, NewCond, true);
+ // Either the 'false' block fallthrough to another block or it ends with a
+ // return. If it's the former, add a conditional branch to its successor.
+ if (!FalseBBI.TrueBB)
+ TII->InsertBranch(*BBI.FalseBB, *BBI.FalseBB->succ_begin(), NULL,NewCond);
+
// Merge the 'true' and 'false' blocks by copying the instructions
// from the 'false' block to the 'true' block.
MergeBlocks(TrueBBI, FalseBBI);
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