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authorMichael Gottesman <mgottesman@apple.com>2013-04-03 23:04:28 +0000
committerMichael Gottesman <mgottesman@apple.com>2013-04-03 23:04:28 +0000
commitca4cb5b6df545517e31a374c7bd8a689aea9a962 (patch)
tree7d2caec18a62283ee8bfed2d15fdde389b68649e /lib/Transforms/ObjCARC
parent60d1c0bca35d78feb780ac831d42ba1688d73461 (diff)
Refactored out a part of ObjCARCOpt::OptimizeReturns into its own method HasSafePathToPredecessorCall.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178710 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/ObjCARC')
-rw-r--r--lib/Transforms/ObjCARC/ObjCARCOpts.cpp55
1 files changed, 33 insertions, 22 deletions
diff --git a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index f4ecf162708..8623433f96d 100644
--- a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -2779,6 +2779,34 @@ bool ObjCARCOpt::OptimizeSequences(Function &F) {
NestingDetected;
}
+// Check if there is a dependent call earlier that does not have anything in
+// between the Retain and the call that can affect the reference count of their
+// shared pointer argument. Note that Retain need not be in BB.
+static bool
+HasSafePathToPredecessorCall(const Value *Arg, Instruction *Retain,
+ SmallPtrSet<Instruction *, 4> &DepInsts,
+ SmallPtrSet<const BasicBlock *, 4> &Visited,
+ ProvenanceAnalysis &PA) {
+ FindDependencies(CanChangeRetainCount, Arg, Retain->getParent(), Retain,
+ DepInsts, Visited, PA);
+ if (DepInsts.size() != 1)
+ return false;
+
+ CallInst *Call =
+ dyn_cast_or_null<CallInst>(*DepInsts.begin());
+
+ // Check that the pointer is the return value of the call.
+ if (!Call || Arg != Call)
+ return false;
+
+ // Check that the call is a regular call.
+ InstructionClass Class = GetBasicInstructionClass(Call);
+ if (Class != IC_CallOrUser && Class != IC_Call)
+ return false;
+
+ return true;
+}
+
/// Look for this pattern:
/// \code
/// %call = call i8* @something(...)
@@ -2840,28 +2868,11 @@ void ObjCARCOpt::OptimizeReturns(Function &F) {
DependingInstructions.clear();
Visited.clear();
-
- // Check that there is nothing that can affect the reference
- // count between the retain and the call.
- // Note that Retain need not be in BB.
- FindDependencies(CanChangeRetainCount, Arg, Retain->getParent(), Retain,
- DependingInstructions, Visited, PA);
- if (DependingInstructions.size() != 1)
- goto next_block;
-
- {
- CallInst *Call =
- dyn_cast_or_null<CallInst>(*DependingInstructions.begin());
-
- // Check that the pointer is the return value of the call.
- if (!Call || Arg != Call)
- goto next_block;
-
- // Check that the call is a regular call.
- InstructionClass Class = GetBasicInstructionClass(Call);
- if (Class != IC_CallOrUser && Class != IC_Call)
- goto next_block;
-
+
+ // Check that there is nothing that can affect the reference count
+ // between the retain and the call. Note that Retain need not be in BB.
+ if (HasSafePathToPredecessorCall(Arg, Retain, DependingInstructions,
+ Visited, PA)) {
// If so, we can zap the retain and autorelease.
Changed = true;
++NumRets;