summaryrefslogtreecommitdiffstats
path: root/lib/Transforms/Scalar/LoopUnswitch.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/Transforms/Scalar/LoopUnswitch.cpp')
-rw-r--r--lib/Transforms/Scalar/LoopUnswitch.cpp68
1 files changed, 33 insertions, 35 deletions
diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp
index e3b809e..27fd2ef 100644
--- a/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -415,46 +415,44 @@ bool LoopUnswitch::UnswitchIfProfitable(Value *LoopCond, Constant *Val) {
Function *F = loopHeader->getParent();
- // If the condition is trivial, always unswitch. There is no code growth for
- // this case.
- if (!IsTrivialUnswitchCondition(LoopCond)) {
- // Check to see if it would be profitable to unswitch current loop.
+ Constant *CondVal = 0;
+ BasicBlock *ExitBlock = 0;
+ if (IsTrivialUnswitchCondition(LoopCond, &CondVal, &ExitBlock)) {
+ // If the condition is trivial, always unswitch. There is no code growth
+ // for this case.
+ UnswitchTrivialCondition(currentLoop, LoopCond, CondVal, ExitBlock);
+ return true;
+ }
- // Do not do non-trivial unswitch while optimizing for size.
- if (OptimizeForSize || F->hasFnAttr(Attribute::OptimizeForSize))
- return false;
+ // Check to see if it would be profitable to unswitch current loop.
- // FIXME: This is overly conservative because it does not take into
- // consideration code simplification opportunities and code that can
- // be shared by the resultant unswitched loops.
- CodeMetrics Metrics;
- for (Loop::block_iterator I = currentLoop->block_begin(),
- E = currentLoop->block_end();
- I != E; ++I)
- Metrics.analyzeBasicBlock(*I);
-
- // Limit the number of instructions to avoid causing significant code
- // expansion, and the number of basic blocks, to avoid loops with
- // large numbers of branches which cause loop unswitching to go crazy.
- // This is a very ad-hoc heuristic.
- if (Metrics.NumInsts > Threshold ||
- Metrics.NumBlocks * 5 > Threshold ||
- Metrics.NeverInline) {
- DEBUG(dbgs() << "NOT unswitching loop %"
- << currentLoop->getHeader()->getName() << ", cost too high: "
- << currentLoop->getBlocks().size() << "\n");
- return false;
- }
- }
+ // Do not do non-trivial unswitch while optimizing for size.
+ if (OptimizeForSize || F->hasFnAttr(Attribute::OptimizeForSize))
+ return false;
- Constant *CondVal;
- BasicBlock *ExitBlock;
- if (IsTrivialUnswitchCondition(LoopCond, &CondVal, &ExitBlock)) {
- UnswitchTrivialCondition(currentLoop, LoopCond, CondVal, ExitBlock);
- } else {
- UnswitchNontrivialCondition(LoopCond, Val, currentLoop);
+ // FIXME: This is overly conservative because it does not take into
+ // consideration code simplification opportunities and code that can
+ // be shared by the resultant unswitched loops.
+ CodeMetrics Metrics;
+ for (Loop::block_iterator I = currentLoop->block_begin(),
+ E = currentLoop->block_end();
+ I != E; ++I)
+ Metrics.analyzeBasicBlock(*I);
+
+ // Limit the number of instructions to avoid causing significant code
+ // expansion, and the number of basic blocks, to avoid loops with
+ // large numbers of branches which cause loop unswitching to go crazy.
+ // This is a very ad-hoc heuristic.
+ if (Metrics.NumInsts > Threshold ||
+ Metrics.NumBlocks * 5 > Threshold ||
+ Metrics.NeverInline) {
+ DEBUG(dbgs() << "NOT unswitching loop %"
+ << currentLoop->getHeader()->getName() << ", cost too high: "
+ << currentLoop->getBlocks().size() << "\n");
+ return false;
}
+ UnswitchNontrivialCondition(LoopCond, Val, currentLoop);
return true;
}
OpenPOWER on IntegriCloud