Akira Hatanaka 90a2aecbed [ObjCARC] Traverse chain downwards to replace uses of argument passed to ... ObjC library call with call return. ARC contraction tries to replace uses of an argument passed to an objective-c library call with the call return value. For example, in the following IR, it replaces uses of argument %9 and uses of the values discovered traversing the chain upwards (%7 and %8) with the call return %10, if they are dominated by the call to @objc_autoreleaseReturnValue. This transformation enables code-gen to tail-call the call to @objc_autoreleaseReturnValue, which is necessary to enable auto release return value optimization. %7 = tail call i8* @objc_loadWeakRetained(i8** %6) %8 = bitcast i8* %7 to %0* %9 = bitcast %0* %8 to i8* %10 = tail call i8* @objc_autoreleaseReturnValue(i8* %9) ret %0* %8 Since r276727, llvm started removing redundant bitcasts and as a result started feeding the following IR to ARC contraction: %7 = tail call i8* @objc_loadWeakRetained(i8** %6) %8 = bitcast i8* %7 to %0* %9 = tail call i8* @objc_autoreleaseReturnValue(i8* %7) ret %0* %8 ARC contraction no longer does the optimization described above since it only traverses the chain upwards and fails to recognize that the function return can be replaced by the call return. This commit changes ARC contraction to traverse the chain downwards too and replace uses of bitcasts with the call return. rdar://problem/28011339 Differential Revision: https://reviews.llvm.org/D24523 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281419 91177308-0d34-0410-b5e6-96231b3b80d8		2016-09-13 23:43:11 +00:00
..
allocas.ll
apelim.ll
basic.ll	[PR27284] Reverse the ownership between DICompileUnit and DISubprogram.	2016-04-15 15:57:41 +00:00
cfg-hazards.ll
comdat-ipo.ll	Don't IPO over functions that can be de-refined	2016-04-08 00:48:30 +00:00
contract-end-of-use-list.ll
contract-marker.ll	Add support for objc_unsafeClaimAutoreleasedReturnValue to the	2016-01-27 19:05:08 +00:00
contract-replace-arg-use.ll	[ObjCARC] Traverse chain downwards to replace uses of argument passed to	2016-09-13 23:43:11 +00:00
contract-storestrong-ivar.ll
contract-storestrong.ll	Form objc_storeStrong in the presence of bitcasts.	2016-05-27 02:13:53 +00:00
contract-testcases.ll
contract.ll
empty-block.ll
ensure-that-exception-unwind-path-is-visited.ll	[PR27284] Reverse the ownership between DICompileUnit and DISubprogram.	2016-04-15 15:57:41 +00:00
escape.ll
expand.ll
gvn.ll
intrinsic-use-isolated.ll
intrinsic-use.ll
invoke.ll
move-and-form-retain-autorelease.ll
move-and-merge-autorelease.ll
nested.ll	Revert "Change memcpy/memset/memmove to have dest and source alignments."	2015-11-19 05:56:52 +00:00
path-overflow.ll	[Verifier] Resume instructions can only be in functions w/ a personality	2016-08-01 18:06:34 +00:00
pointer-types.ll
post-inlining.ll
pr12270.ll
provenance.ll	[PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible	2015-09-09 17:55:00 +00:00
retain-block-side-effects.ll
retain-not-declared.ll
rle-s2l.ll
rv.ll
split-backedge.ll
tail-call-invariant-enforcement.ll	Add support for objc_unsafeClaimAutoreleasedReturnValue to the	2016-01-27 19:05:08 +00:00
unsafe-claim-rv.ll	[ObjCARC] Handle ARCInstKind::ClaimRV in OptimizeIndividualCalls.	2016-02-17 18:51:27 +00:00
weak-contract.ll
weak-copies.ll
weak-dce.ll
weak.ll