instcombine: disable optimization of 'invoke null/undef'. I'll move this functionality to SimplifyCFG (since we cannot make changes to the CFG here).

Fixes the crashes with the attached test case

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158951 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 58 insertions, 11 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index b638cc2..f74cff8 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -917,24 +917,24 @@ Instruction *InstCombiner::visitCallSite(CallSite CS) {
     }
 
   if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) {
-    // This instruction is not reachable, just remove it.  We insert a store to
-    // undef so that we know that this code is not reachable, despite the fact
-    // that we can't modify the CFG here.
-    new StoreInst(ConstantInt::getTrue(Callee->getContext()),
-               UndefValue::get(Type::getInt1PtrTy(Callee->getContext())),
-                  CS.getInstruction());
-
     // If CS does not return void then replaceAllUsesWith undef.
     // This allows ValueHandlers and custom metadata to adjust itself.
     if (!CS.getInstruction()->getType()->isVoidTy())
       ReplaceInstUsesWith(*CS.getInstruction(),
                           UndefValue::get(CS.getInstruction()->getType()));
 
-    if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
-      // Don't break the CFG, insert a dummy cond branch.
-      BranchInst::Create(II->getNormalDest(), II->getUnwindDest(),
-                         ConstantInt::getTrue(Callee->getContext()), II);
+    if (isa<InvokeInst>(CS.getInstruction())) {
+      // Can't remove an invoke because we cannot change the CFG.
+      return 0;
     }
+
+    // This instruction is not reachable, just remove it.  We insert a store to
+    // undef so that we know that this code is not reachable, despite the fact
+    // that we can't modify the CFG here.
+    new StoreInst(ConstantInt::getTrue(Callee->getContext()),
+                  UndefValue::get(Type::getInt1PtrTy(Callee->getContext())),
+                  CS.getInstruction());
+
     return EraseInstFromFunction(*CS.getInstruction());
   }
 
diff --git a/test/Transforms/InstCombine/invoke.ll b/test/Transforms/InstCombine/invoke.ll
new file mode 100644
index 0000000..ea3564d
--- /dev/null
+++ b/test/Transforms/InstCombine/invoke.ll
@@ -0,0 +1,47 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+
+declare i32 @__gxx_personality_v0(...)
+declare void @__cxa_call_unexpected(i8*)
+declare i64 @llvm.objectsize.i64(i8*, i1) nounwind readonly
+
+
+; CHECK: @f1
+define i64 @f1() nounwind uwtable ssp {
+entry:
+; CHECK: nvoke noalias i8* undef()
+  %call = invoke noalias i8* undef()
+          to label %invoke.cont unwind label %lpad
+
+invoke.cont:
+; CHECK: ret i64 0
+  %0 = tail call i64 @llvm.objectsize.i64(i8* %call, i1 false)
+  ret i64 %0
+
+lpad:
+  %1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          filter [0 x i8*] zeroinitializer
+  %2 = extractvalue { i8*, i32 } %1, 0
+  tail call void @__cxa_call_unexpected(i8* %2) noreturn nounwind
+  unreachable
+}
+
+; CHECK: @f2
+define i64 @f2() nounwind uwtable ssp {
+entry:
+; CHECK: nvoke noalias i8* null()
+  %call = invoke noalias i8* null()
+          to label %invoke.cont unwind label %lpad
+
+invoke.cont:
+; CHECK: ret i64 0
+  %0 = tail call i64 @llvm.objectsize.i64(i8* %call, i1 false)
+  ret i64 %0
+
+lpad:
+  %1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          filter [0 x i8*] zeroinitializer
+  %2 = extractvalue { i8*, i32 } %1, 0
+  tail call void @__cxa_call_unexpected(i8* %2) noreturn nounwind
+  unreachable
+}