[Attributor] Fix: Gracefully handle non-instruction users

Function can have users that are not instructions, e.g., bitcasts. For
now, we simply give up when we see them.

llvm-svn: 369588

2 files changed, 28 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index 71daf79a04d..6caa0275c7d 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -2321,7 +2321,11 @@ bool Attributor::checkForAllCallSites(const function_ref<bool(CallSite)> &Pred,
   }
 
   for (const Use &U : AssociatedFunction->uses()) {
-    Instruction *I = cast<Instruction>(U.getUser());
+    Instruction *I = dyn_cast<Instruction>(U.getUser());
+    // TODO: Deal with abstract call sites here.
+    if (!I)
+      return false;
+
     Function *Caller = I->getFunction();
 
     const auto &LivenessAA =
diff --git a/llvm/test/Transforms/FunctionAttrs/misc.ll b/llvm/test/Transforms/FunctionAttrs/misc.ll
new file mode 100644
index 00000000000..96ceb8743fd
--- /dev/null
+++ b/llvm/test/Transforms/FunctionAttrs/misc.ll
@@ -0,0 +1,23 @@
+; RUN: opt -S -attributor -attributor-disable=false < %s | FileCheck %s
+
+define void @external() {
+entry:
+  %a = alloca i32, align 4
+  %tmp = bitcast i32* %a to i8*
+  call void @foo(i32* nonnull %a)
+; Check we do not crash on these uses
+; CHECK: call void @callback1(void (i32*)* nonnull @foo)
+  call void @callback1(void (i32*)* nonnull @foo)
+; CHECK: call void @callback2(void (i8*)* nonnull bitcast (void (i32*)* @foo to void (i8*)*))
+  call void @callback2(void (i8*)* bitcast (void (i32*)* @foo to void (i8*)*))
+  %tmp1 = bitcast i32* %a to i8*
+  ret void
+}
+
+define internal void @foo(i32* %a) {
+entry:
+  ret void
+}
+
+declare void @callback1(void (i32*)*)
+declare void @callback2(void (i8*)*)