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Factor out the predicate code for loopsimplify form exit blocks into

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a separate helper function.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86159 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-11-05 19:21:41 +00:00
parent b5b10c25f7
commit f17e9511f1
2 changed files with 12 additions and 6 deletions
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4
include/llvm/Analysis/LoopInfo.h
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@ -572,6 +572,10 @@ public:
/// normal form.
bool isLoopSimplifyForm() const;
/// hasDedicatedExits - Return true if no exit block for the loop
/// has a predecessor that is outside the loop.
bool hasDedicatedExits() const;
/// getUniqueExitBlocks - Return all unique successor blocks of this loop.
/// These are the blocks _outside of the current loop_ which are branched to.
/// This assumes that loop is in canonical form.

14
lib/Analysis/LoopInfo.cpp
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@ -286,12 +286,14 @@ bool Loop::isLCSSAForm() const {
/// the LoopSimplify form transforms loops to, which is sometimes called
/// normal form.
bool Loop::isLoopSimplifyForm() const {
// Normal-form loops have a preheader.
if (!getLoopPreheader())
return false;
// Normal-form loops have a single backedge.
if (!getLoopLatch())
return false;
// Normal-form loops have a preheader, a single backedge, and all of their
// exits have all their predecessors inside the loop.
return getLoopPreheader() && getLoopLatch() && hasDedicatedExits();
}
/// hasDedicatedExits - Return true if no exit block for the loop
/// has a predecessor that is outside the loop.
bool Loop::hasDedicatedExits() const {
// Sort the blocks vector so that we can use binary search to do quick
// lookups.
SmallPtrSet<BasicBlock *, 16> LoopBBs(block_begin(), block_end());