[llvm] r250784 - [RS4GC] Re-purpose `normalizeForInvokeSafepoint`; NFC.

[Sanjoy Das via llvm-commits]

Author: sanjoy
Date: Mon Oct 19 20:06:24 2015
New Revision: 250784

URL: http://llvm.org/viewvc/llvm-project?rev=250784&view=rev
Log:
[RS4GC] Re-purpose `normalizeForInvokeSafepoint`; NFC.

`normalizeForInvokeSafepoint` in RewriteStatepointsForGC.cpp, as it is
written today, deals with `gc.relocate` and `gc.result` uses of a
statepoint equally well.  This change documents this fact and adds a
test case.

There is no functional change here -- only documentation of existing
functionality.

Added:
    llvm/trunk/test/Transforms/RewriteStatepointsForGC/deopt-bundles/rewrite-invoke.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp?rev=250784&r1=250783&r2=250784&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp Mon Oct 19 20:06:24 2015
@@ -1239,12 +1239,12 @@ static void recomputeLiveInValues(
   }
 }
 
-// When inserting gc.relocate calls, we need to ensure there are no uses
-// of the original value between the gc.statepoint and the gc.relocate call.
-// One case which can arise is a phi node starting one of the successor blocks.
-// We also need to be able to insert the gc.relocates only on the path which
-// goes through the statepoint.  We might need to split an edge to make this
-// possible.
+// When inserting gc.relocate and gc.result calls, we need to ensure there are
+// no uses of the original value / return value between the gc.statepoint and
+// the gc.relocate / gc.result call.  One case which can arise is a phi node
+// starting one of the successor blocks.  We also need to be able to insert the
+// gc.relocates only on the path which goes through the statepoint.  We might
+// need to split an edge to make this possible.
 static BasicBlock *
 normalizeForInvokeSafepoint(BasicBlock *BB, BasicBlock *InvokeParent,
                             DominatorTree &DT) {
@@ -1252,14 +1252,14 @@ normalizeForInvokeSafepoint(BasicBlock *
   if (!BB->getUniquePredecessor())
     Ret = SplitBlockPredecessors(BB, InvokeParent, "", &DT);
 
-  // Now that 'ret' has unique predecessor we can safely remove all phi nodes
+  // Now that 'Ret' has unique predecessor we can safely remove all phi nodes
   // from it
   FoldSingleEntryPHINodes(Ret);
   assert(!isa<PHINode>(Ret->begin()) &&
          "All PHI nodes should have been removed!");
 
-  // At this point, we can safely insert a gc.relocate as the first instruction
-  // in Ret if needed.
+  // At this point, we can safely insert a gc.relocate or gc.result as the first
+  // instruction in Ret if needed.
   return Ret;
 }
 

Added: llvm/trunk/test/Transforms/RewriteStatepointsForGC/deopt-bundles/rewrite-invoke.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/RewriteStatepointsForGC/deopt-bundles/rewrite-invoke.ll?rev=250784&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/RewriteStatepointsForGC/deopt-bundles/rewrite-invoke.ll (added)
+++ llvm/trunk/test/Transforms/RewriteStatepointsForGC/deopt-bundles/rewrite-invoke.ll Mon Oct 19 20:06:24 2015
@@ -0,0 +1,32 @@
+; RUN: opt -rewrite-statepoints-for-gc -rs4gc-use-deopt-bundles -verify -S < %s | FileCheck %s
+
+declare i8 addrspace(1)* @gc_call()
+
+declare i32* @fake_personality_function()
+
+define i8 addrspace(1)* @test(i1 %c) gc "statepoint-example" personality i32* ()* @fake_personality_function {
+; CHECK-LABEL: @test(
+entry:
+  br i1 %c, label %gc_invoke, label %normal_dest
+
+gc_invoke:
+; CHECK: [[TOKEN:%[^ ]+]] = invoke i32 {{[^@]+}}@llvm.experimental.gc.statepoint{{[^@]+}}@gc_call
+  %obj = invoke i8 addrspace(1)* @gc_call() [ "deopt"(i32 0, i32 -1, i32 0, i32 0, i32 0) ]
+          to label %normal_dest unwind label %unwind_dest
+
+unwind_dest:
+; CHECK: unwind_dest:
+  %lpad = landingpad { i8*, i32 }
+          cleanup
+  resume { i8*, i32 } undef
+
+; CHECK: [[NORMAL_DEST_SPLIT:[^:]+:]]
+; CHECK-NEXT: [[RET_VAL:%[^ ]+]] = call i8 addrspace(1)* @llvm.experimental.gc.result.p1i8(i32 [[TOKEN]])
+; CHECK-NEXT: br label %normal_dest
+
+normal_dest:
+; CHECK: normal_dest:
+; CHECK-NEXT: %merge = phi i8 addrspace(1)* [ null, %entry ], [ %obj.2, %normal_dest1 ]
+  %merge = phi i8 addrspace(1)* [ null, %entry ], [ %obj, %gc_invoke ]
+  ret i8 addrspace(1)* %merge
+}