#include "llvm/Analysis/Dominators.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Support/Compiler.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h"
if (!L->isLoopInvariant(SplitValue))
return false;
Instruction *OPI = dyn_cast<Instruction>(OPV);
- if (!OPI) return false;
+ if (!OPI)
+ return false;
if (OPI->getParent() != Header || isUsedOutsideLoop(OPI, L))
return false;
-
+ Value *StartValue = IVStartValue;
+ Value *ExitValue = IVExitValue;;
+
+ if (OPV != IndVar) {
+ // If BR operand is IV based then use this operand to calculate
+ // effective conditions for loop body.
+ BinaryOperator *BOPV = dyn_cast<BinaryOperator>(OPV);
+ if (!BOPV)
+ return false;
+ if (BOPV->getOpcode() != Instruction::Add)
+ return false;
+ StartValue = BinaryOperator::CreateAdd(OPV, StartValue, "" , BR);
+ ExitValue = BinaryOperator::CreateAdd(OPV, ExitValue, "" , BR);
+ }
+
if (!cleanBlock(Header))
return false;
// and i32 c1, c2
Instruction *C1 = new ICmpInst(ExitCondition->isSignedPredicate() ?
ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE,
- SplitValue, IVStartValue, "lisplit", BR);
+ SplitValue, StartValue, "lisplit", BR);
CmpInst::Predicate C2P = ExitCondition->getPredicate();
BranchInst *LatchBR = cast<BranchInst>(Latch->getTerminator());
if (LatchBR->getOperand(0) != Header)
C2P = CmpInst::getInversePredicate(C2P);
- Instruction *C2 = new ICmpInst(C2P, SplitValue, IVExitValue, "lisplit", BR);
+ Instruction *C2 = new ICmpInst(C2P, SplitValue, ExitValue, "lisplit", BR);
Instruction *NSplitCond = BinaryOperator::CreateAnd(C1, C2, "lisplit", BR);
SplitCondition->replaceAllUsesWith(NSplitCond);
if (Header != *SI)
LatchSucc = *SI;
}
- LatchBR->setUnconditionalDest(LatchSucc);
- // Remove IVIncrement
- IVIncrement->replaceAllUsesWith(UndefValue::get(IVIncrement->getType()));
- IVIncrement->eraseFromParent();
+ // Clean up latch block.
+ Value *LatchBRCond = LatchBR->getCondition();
+ LatchBR->setUnconditionalDest(LatchSucc);
+ RecursivelyDeleteTriviallyDeadInstructions(LatchBRCond);
LPM->deleteLoopFromQueue(L);
--- /dev/null
+; RUN: llvm-as < %s | opt -loop-index-split | llvm-dis | not grep undef
+define i32 @main() {
+entry:
+ br label %header
+
+header:
+ %r = phi i32 [ 0, %entry ], [ %r3, %skip ]
+ %i = phi i32 [ 0, %entry ], [ %i1, %skip ]
+ %i99 = add i32 %i, 99
+ %cond = icmp eq i32 %i99, 3
+ br i1 %cond, label %body, label %skip
+
+body:
+ br label %skip
+
+skip:
+ %r3 = phi i32 [ %r, %header ], [ 3, %body ]
+ %i1 = add i32 %i, 1
+ %exitcond = icmp eq i32 %i1, 10
+ br i1 %exitcond, label %exit, label %header
+
+exit:
+ ret i32 %r3
+}