[llvm-commits] [llvm] r154647 - in /llvm/trunk: lib/Transforms/Scalar/ObjCARC.cpp test/Transforms/ObjCARC/contract.ll

[Dan Gohman]

Author: djg
Date: Thu Apr 12 20:08:28 2012
New Revision: 154647

URL: http://llvm.org/viewvc/llvm-project?rev=154647&view=rev
Log:
Use the new Use-aware dominates method to apply the objc runtime
library return value optimization for phi uses. Even when the
phi itself is not dominated, the specific use may be dominated.

Modified:
    llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp
    llvm/trunk/test/Transforms/ObjCARC/contract.ll

Modified: llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp?rev=154647&r1=154646&r2=154647&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp Thu Apr 12 20:08:28 2012
@@ -4109,16 +4109,12 @@
         Use &U = UI.getUse();
         unsigned OperandNo = UI.getOperandNo();
         ++UI; // Increment UI now, because we may unlink its element.
-        Instruction *UserInst = dyn_cast<Instruction>(U.getUser());
-        if (!UserInst)
-          continue;
-        // FIXME: dominates should return true for unreachable UserInst.
-        if (DT->isReachableFromEntry(UserInst->getParent()) &&
-            DT->dominates(Inst, UserInst)) {
+        if (DT->isReachableFromEntry(U) &&
+            DT->dominates(Inst, U)) {
           Changed = true;
           Instruction *Replacement = Inst;
           Type *UseTy = U.get()->getType();
-          if (PHINode *PHI = dyn_cast<PHINode>(UserInst)) {
+          if (PHINode *PHI = dyn_cast<PHINode>(U.getUser())) {
             // For PHI nodes, insert the bitcast in the predecessor block.
             unsigned ValNo =
               PHINode::getIncomingValueNumForOperand(OperandNo);
@@ -4139,7 +4135,8 @@
               }
           } else {
             if (Replacement->getType() != UseTy)
-              Replacement = new BitCastInst(Replacement, UseTy, "", UserInst);
+              Replacement = new BitCastInst(Replacement, UseTy, "",
+                                            cast<Instruction>(U.getUser()));
             U.set(Replacement);
           }
         }

Modified: llvm/trunk/test/Transforms/ObjCARC/contract.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ObjCARC/contract.ll?rev=154647&r1=154646&r2=154647&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/ObjCARC/contract.ll (original)
+++ llvm/trunk/test/Transforms/ObjCARC/contract.ll Thu Apr 12 20:08:28 2012
@@ -143,3 +143,21 @@
   %2 = tail call i8* @objc_autoreleaseReturnValue(i8* %p)
   ret i8* %p
 }
+
+; Do the return value substitution for PHI nodes too.
+
+; CHECK: define i8* @test8(
+; CHECK: %retval = phi i8* [ %p, %if.then ], [ null, %entry ]
+; CHECK: }
+define i8* @test8(i1 %x, i8* %c) {
+entry:
+  br i1 %x, label %return, label %if.then
+
+if.then:                                          ; preds = %entry
+  %p = call i8* @objc_retain(i8* %c) nounwind
+  br label %return
+
+return:                                           ; preds = %if.then, %entry
+  %retval = phi i8* [ %c, %if.then ], [ null, %entry ]
+  ret i8* %retval
+}