From e8b3c2e48aa597f08d029ecaed6c1f7ae3a1d111 Mon Sep 17 00:00:00 2001
From: Michael Gottesman <mgottesman@apple.com>
Date: Fri, 5 Apr 2013 22:54:32 +0000
Subject: [PATCH] An objc_retain can serve as a use for a different pointer.

This is the counterpart to commit r160637, except it performs the action
in the bottomup portion of the data flow analysis.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178922 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/ObjCARC/ObjCARCOpts.cpp |  5 +-
 test/Transforms/ObjCARC/basic.ll       | 95 ++++++++++++++++++++++++++
 2 files changed, 98 insertions(+), 2 deletions(-)

diff --git a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index 9f59b68d68a..acc32d5eb31 100644
--- a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -1817,8 +1817,9 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst,
     case S_Retain:
       llvm_unreachable("bottom-up pointer in retain state!");
     }
-    ANNOTATE_BOTTOMUP(Inst, Arg, OldSeq, S.GetSeq());
-    return NestingDetected;
+    ANNOTATE_BOTTOMUP(Inst, Arg, OldSeq, S.GetSeq());    
+    // A retain moving bottom up can be a use.
+    break;
   }
   case IC_AutoreleasepoolPop:
     // Conservatively, clear MyStates for all known pointers.
diff --git a/test/Transforms/ObjCARC/basic.ll b/test/Transforms/ObjCARC/basic.ll
index 021aebb126f..670e697e522 100644
--- a/test/Transforms/ObjCARC/basic.ll
+++ b/test/Transforms/ObjCARC/basic.ll
@@ -2607,6 +2607,101 @@ return:                                           ; preds = %if.then, %entry
   ret i8* %retval
 }
 
+; An objc_retain can serve as a may-use for a different pointer.
+; rdar://11931823
+
+; CHECK: define void @test66a(
+; CHECK:   tail call i8* @objc_retain(i8* %cond) [[NUW]]
+; CHECK:   tail call void @objc_release(i8* %call) [[NUW]]
+; CHECK:   tail call i8* @objc_retain(i8* %tmp8) [[NUW]]
+; CHECK:   tail call void @objc_release(i8* %cond) [[NUW]]
+; CHECK: }
+define void @test66a(i8* %tmp5, i8* %bar, i1 %tobool, i1 %tobool1, i8* %call) {
+entry:
+  br i1 %tobool, label %cond.true, label %cond.end
+
+cond.true:
+  br label %cond.end
+
+cond.end:                                         ; preds = %cond.true, %entry
+  %cond = phi i8* [ %tmp5, %cond.true ], [ %call, %entry ]
+  %tmp7 = tail call i8* @objc_retain(i8* %cond) nounwind
+  tail call void @objc_release(i8* %call) nounwind
+  %tmp8 = select i1 %tobool1, i8* %cond, i8* %bar
+  %tmp9 = tail call i8* @objc_retain(i8* %tmp8) nounwind
+  tail call void @objc_release(i8* %cond) nounwind
+  ret void
+}
+
+; CHECK: define void @test66b(
+; CHECK:   tail call i8* @objc_retain(i8* %cond) [[NUW]]
+; CHECK:   tail call void @objc_release(i8* %call) [[NUW]]
+; CHECK:   tail call i8* @objc_retain(i8* %tmp8) [[NUW]]
+; CHECK:   tail call void @objc_release(i8* %cond) [[NUW]]
+; CHECK: }
+define void @test66b(i8* %tmp5, i8* %bar, i1 %tobool, i1 %tobool1, i8* %call) {
+entry:
+  br i1 %tobool, label %cond.true, label %cond.end
+
+cond.true:
+  br label %cond.end
+
+cond.end:                                         ; preds = %cond.true, %entry
+  %cond = phi i8* [ %tmp5, %cond.true ], [ %call, %entry ]
+  %tmp7 = tail call i8* @objc_retain(i8* %cond) nounwind
+  tail call void @objc_release(i8* %call) nounwind, !clang.imprecise_release !0
+  %tmp8 = select i1 %tobool1, i8* %cond, i8* %bar
+  %tmp9 = tail call i8* @objc_retain(i8* %tmp8) nounwind
+  tail call void @objc_release(i8* %cond) nounwind
+  ret void
+}
+
+; CHECK: define void @test66c(
+; CHECK:   tail call i8* @objc_retain(i8* %cond) [[NUW]]
+; CHECK:   tail call void @objc_release(i8* %call) [[NUW]]
+; CHECK:   tail call i8* @objc_retain(i8* %tmp8) [[NUW]]
+; CHECK:   tail call void @objc_release(i8* %cond) [[NUW]]
+; CHECK: }
+define void @test66c(i8* %tmp5, i8* %bar, i1 %tobool, i1 %tobool1, i8* %call) {
+entry:
+  br i1 %tobool, label %cond.true, label %cond.end
+
+cond.true:
+  br label %cond.end
+
+cond.end:                                         ; preds = %cond.true, %entry
+  %cond = phi i8* [ %tmp5, %cond.true ], [ %call, %entry ]
+  %tmp7 = tail call i8* @objc_retain(i8* %cond) nounwind
+  tail call void @objc_release(i8* %call) nounwind
+  %tmp8 = select i1 %tobool1, i8* %cond, i8* %bar
+  %tmp9 = tail call i8* @objc_retain(i8* %tmp8) nounwind, !clang.imprecise_release !0
+  tail call void @objc_release(i8* %cond) nounwind
+  ret void
+}
+
+; CHECK: define void @test66d(
+; CHECK:   tail call i8* @objc_retain(i8* %cond) [[NUW]]
+; CHECK:   tail call void @objc_release(i8* %call) [[NUW]]
+; CHECK:   tail call i8* @objc_retain(i8* %tmp8) [[NUW]]
+; CHECK:   tail call void @objc_release(i8* %cond) [[NUW]]
+; CHECK: }
+define void @test66d(i8* %tmp5, i8* %bar, i1 %tobool, i1 %tobool1, i8* %call) {
+entry:
+  br i1 %tobool, label %cond.true, label %cond.end
+
+cond.true:
+  br label %cond.end
+
+cond.end:                                         ; preds = %cond.true, %entry
+  %cond = phi i8* [ %tmp5, %cond.true ], [ %call, %entry ]
+  %tmp7 = tail call i8* @objc_retain(i8* %cond) nounwind
+  tail call void @objc_release(i8* %call) nounwind, !clang.imprecise_release !0
+  %tmp8 = select i1 %tobool1, i8* %cond, i8* %bar
+  %tmp9 = tail call i8* @objc_retain(i8* %tmp8) nounwind
+  tail call void @objc_release(i8* %cond) nounwind, !clang.imprecise_release !0
+  ret void
+}
+
 ; A few real-world testcases.
 
 @.str4 = private unnamed_addr constant [33 x i8] c"-[A z] = { %f, %f, { %f, %f } }\0A\00"