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split a complex predicate out to a helper function. Simplify two for loops, 

which don't need to check for falling off the end of a block *and* end of phi
nodes, since terminators are never phis.

llvm-svn: 129655
This commit is contained in:
Chris Lattner 2011-04-17 06:03:19 +00:00
parent 55f7bf3289
commit d70ff0d807
1 changed files with 16 additions and 10 deletions
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26
llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
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@ -830,6 +830,17 @@ static void CheckLineNumbers(const MachineBasicBlock *MBB) {
}
#endif
/// isFoldedOrDeadInstruction - Return true if the specified instruction is
/// side-effect free and is either dead or folded into a generated instruction.
/// Return false if it needs to be emitted.
static bool isFoldedOrDeadInstruction(const Instruction *I,
FunctionLoweringInfo *FuncInfo) {
return !I->mayWriteToMemory() &&
!isa<TerminatorInst>(I) &&
!isa<DbgInfoIntrinsic>(I) &&
!FuncInfo->isExportedInst(I);
}
void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
// Initialize the Fast-ISel state, if needed.
FastISel *FastIS = 0;
@ -856,15 +867,13 @@ void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
}
if (AllPredsVisited) {
for (BasicBlock::const_iterator I = LLVMBB->begin(), E = LLVMBB->end();
I != E && isa<PHINode>(I); ++I) {
for (BasicBlock::const_iterator I = LLVMBB->begin();
isa<PHINode>(I); ++I)
FuncInfo->ComputePHILiveOutRegInfo(cast<PHINode>(I));
}
} else {
for (BasicBlock::const_iterator I = LLVMBB->begin(), E = LLVMBB->end();
I != E && isa<PHINode>(I); ++I) {
for (BasicBlock::const_iterator I = LLVMBB->begin();
isa<PHINode>(I); ++I)
FuncInfo->InvalidatePHILiveOutRegInfo(cast<PHINode>(I));
}
}
FuncInfo->VisitedBBs.insert(LLVMBB);
@ -912,10 +921,7 @@ void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
const Instruction *Inst = llvm::prior(BI);
// If we no longer require this instruction, skip it.
if (!Inst->mayWriteToMemory() &&
!isa<TerminatorInst>(Inst) &&
!isa<DbgInfoIntrinsic>(Inst) &&
!FuncInfo->isExportedInst(Inst))
if (isFoldedOrDeadInstruction(Inst, FuncInfo))
continue;
// Bottom-up: reset the insert pos at the top, after any local-value