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Give 'hasPath' a longer but clearer name 'isPotentiallyReachable'. Also expand

the comment. No functionality change. This change broken out of
http://llvm-reviews.chandlerc.com/D996 .


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186558 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2013-07-18 02:34:51 +00:00
parent 7a8503c411
commit 717b3f02ff

@ -361,9 +361,11 @@ AliasAnalysis::getModRefInfo(const AtomicRMWInst *RMW, const Location &Loc) {
}
namespace {
// Conservatively return true. Return false, if there is a single path
// starting from "From" and the path does not reach "To".
static bool hasPath(const BasicBlock *From, const BasicBlock *To) {
/// Determine whether there is a path from From to To within a single
/// function. Returns false only if we can prove that once 'From' has been
/// executed then 'To' can not be executed. Conservatively returns true.
static bool isPotentiallyReachable(const BasicBlock *From,
const BasicBlock *To) {
const unsigned MaxCheck = 5;
const BasicBlock *Current = From;
for (unsigned I = 0; I < MaxCheck; I++) {
@ -400,7 +402,7 @@ namespace {
// there is no need to explore the use if BeforeHere dominates use.
// Check whether there is a path from I to BeforeHere.
if (BeforeHere != I && DT->dominates(BeforeHere, I) &&
!hasPath(BB, BeforeHere->getParent()))
!isPotentiallyReachable(BB, BeforeHere->getParent()))
return false;
return true;
}
@ -412,7 +414,7 @@ namespace {
if (BeforeHere != I && !DT->isReachableFromEntry(BB))
return false;
if (BeforeHere != I && DT->dominates(BeforeHere, I) &&
!hasPath(BB, BeforeHere->getParent()))
!isPotentiallyReachable(BB, BeforeHere->getParent()))
return false;
Captured = true;
return true;