Merging r155954:

------------------------------------------------------------------------
r155954 | void | 2012-05-01 15:50:45 -0700 (Tue, 01 May 2012) | 3 lines

Strip the pointer casts off of allocas so that the selection DAG can find them.
PR10799

------------------------------------------------------------------------


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_31@155955 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -5050,7 +5050,7 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
   }
   case Intrinsic::gcroot:
     if (GFI) {
-      const Value *Alloca = I.getArgOperand(0);
+      const Value *Alloca = I.getArgOperand(0)->stripPointerCasts();
       const Constant *TypeMap = cast<Constant>(I.getArgOperand(1));
 
       FrameIndexSDNode *FI = cast<FrameIndexSDNode>(getValue(Alloca).getNode());

test/CodeGen/X86/GC/cg-O0.ll

@@ -0,0 +1,17 @@
+; RUN: llc < %s -O0
+
+define i32 @main() {
+entry:
+  call void @f()
+  ret i32 0
+}
+
+define void @f() gc "ocaml" {
+entry:
+  %ptr.stackref = alloca i8*
+  %gcroot = bitcast i8** %ptr.stackref to i8**
+  call void @llvm.gcroot(i8** %gcroot, i8* null)
+  ret void
+}
+
+declare void @llvm.gcroot(i8**, i8*) nounwind