From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Thu, 15 Dec 2016 21:23:44 +0000 (+0000)
Subject: [Verifier] Allow TBAA metadata on atomicrmw and atomiccmpxchg
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=8cf1000f92e4667ae67de25429287a869369bd8d;p=llvm

[Verifier] Allow TBAA metadata on atomicrmw and atomiccmpxchg

This used to be allowed before r289402 by default (before r289402 you
could have TBAA metadata on any instruction), and while I'm not sure
that it helps, it does sound reasonable enough to not fail the verifier
and we have out-of-tree users who use this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289872 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/IR/Verifier.cpp b/lib/IR/Verifier.cpp
index 34f7bf16849..3609628561b 100644
--- a/lib/IR/Verifier.cpp
+++ b/lib/IR/Verifier.cpp
@@ -4062,7 +4062,8 @@ void Verifier::visitInstruction(Instruction &I) {
 
   if (MDNode *TBAA = I.getMetadata(LLVMContext::MD_tbaa)) {
     Assert(isa<LoadInst>(I) || isa<StoreInst>(I) || isa<CallInst>(I) ||
-               isa<VAArgInst>(I),
+               isa<VAArgInst>(I) || isa<AtomicRMWInst>(I) ||
+               isa<AtomicCmpXchgInst>(I),
            "TBAA is only for loads, stores and calls!", &I);
     visitTBAAMetadata(I, TBAA);
   }
diff --git a/test/Verifier/tbaa-allowed.ll b/test/Verifier/tbaa-allowed.ll
new file mode 100644
index 00000000000..911d3caa29a
--- /dev/null
+++ b/test/Verifier/tbaa-allowed.ll
@@ -0,0 +1,22 @@
+; RUN: opt -S < %s
+
+; This file contains TBAA metadata that is okay and should pass the verifier.
+
+declare void @callee()
+declare void @llvm.va_start(i8*) nounwind
+
+define void @f_0(i8* %ptr, ...) {
+  %args = alloca i8, align 8
+  call void @llvm.va_start(i8* %args)
+
+  %old = atomicrmw add i8* %ptr, i8 0 seq_cst,          !tbaa !{!1, !1, i64 0}
+  %pair = cmpxchg i8* %ptr, i8 0, i8 1 acquire acquire, !tbaa !{!1, !1, i64 0}
+  %ld = load i8, i8* %ptr,                              !tbaa !{!1, !1, i64 0}
+  store i8 1, i8* %ptr,                                 !tbaa !{!1, !1, i64 0}
+  call void @callee(),                                  !tbaa !{!1, !1, i64 0}
+  %argval = va_arg i8* %args, i8,                       !tbaa !{!1, !1, i64 0}
+  ret void
+}
+
+!0 = !{!"root"}
+!1 = !{!"scalar-a", !0}