[PATCH] [RewriteStatepointsForGC] Fix a relocation bug w.r.t values defined by invoke instructions

[Chen Li]

Update patch w.r.t Sanjoy's comments.


http://reviews.llvm.org/D7923

Files:
  lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
  test/Transforms/RewriteStatepointsForGC/relocate_invoke_result.ll

Index: lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
===================================================================
--- lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
+++ lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
@@ -1559,8 +1559,18 @@
     // store must be inserted after load, otherwise store will be in alloca's
     // use list and an extra load will be inserted before it
     StoreInst *store = new StoreInst(def, alloca);
-    if (isa<Instruction>(def)) {
-      store->insertAfter(cast<Instruction>(def));
+    if (Instruction *inst = dyn_cast<Instruction>(def)) {
+      if (InvokeInst *invoke = dyn_cast<InvokeInst>(inst)) {
+        // InvokeInst is a TerminatorInst so the store need to be inserted
+        // into its normal destination block.
+        BasicBlock *normalDest = invoke->getNormalDest();
+        store->insertBefore(normalDest->getFirstNonPHI());
+      } else {
+        assert(!inst->isTerminator() &&
+               "The only TerminatorInst that can produce a value is "
+               "InvokeInst which is handled above.");
+         store->insertAfter(inst);
+      }
     } else {
       assert((isa<Argument>(def) || isa<GlobalVariable>(def) ||
               (isa<Constant>(def) && cast<Constant>(def)->isNullValue())) &&
Index: test/Transforms/RewriteStatepointsForGC/relocate_invoke_result.ll
===================================================================
--- test/Transforms/RewriteStatepointsForGC/relocate_invoke_result.ll
+++ test/Transforms/RewriteStatepointsForGC/relocate_invoke_result.ll
@@ -0,0 +1,30 @@
+;; RUN: opt %s -rewrite-statepoints-for-gc -verify -S 
+
+;; This test is to verify that RewriteStatepointsForGC correctly relocates values
+;; defined by invoke instruction results. 
+
+declare i64* addrspace(1)* @non_gc_call()
+
+declare void @gc_call()
+
+declare i32* @fake_personality_function()
+
+; Function Attrs: nounwind
+define i64* addrspace(1)* @test() gc "statepoint-example" {
+entry:
+  %obj = invoke i64* addrspace(1)* @non_gc_call()
+          to label %normal_dest unwind label %unwind_dest
+
+unwind_dest:                                      ; preds = %entry
+  %lpad = landingpad { i8*, i32 } personality i32* ()* @fake_personality_function
+          cleanup
+  resume { i8*, i32 } undef
+
+normal_dest:                                      ; preds = %entry
+  %safepoint_token = call i32 (void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(void ()* @gc_call, i32 0, i32 0, i32 5, i32 0, i32 -1, i32 0, i32 0, i32 0)
+  ret i64* addrspace(1)* %obj
+}
+
+declare i32 @llvm.experimental.gc.statepoint.p0f_isVoidf(void ()*, i32, i32, ...)
+
+

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