From: Philip Reames <listmail@philipreames.com>
Date: Tue, 19 Mar 2019 17:20:49 +0000 (+0000)
Subject: [PATCH] [AtomicExpand] Fix a crash bug when lowering unordered loads to cmpxchg
X-Git-Tag: archive/raspbian/1%7.0.1-8+rpi3+deb10u2^2~3
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=9c032c5c3b64b18087742a350f38e19302a3d91d;p=llvm-toolchain-7.git

[PATCH] [AtomicExpand] Fix a crash bug when lowering unordered loads to cmpxchg

Add tests for wider atomic loads and stores.  In the process, fix a crasher where we appearently handled unorder stores, but not loads, when lowering to cmpxchg idioms.

llvm-svn: 356482

Gbp-Pq: Name AtomicExpand-Fix-a-crash-bug-when-lowering-unordered-loads.patch
---

diff --git a/lib/CodeGen/AtomicExpandPass.cpp b/lib/CodeGen/AtomicExpandPass.cpp
index e28fc6fb9..b58490f1e 100644
--- a/lib/CodeGen/AtomicExpandPass.cpp
+++ b/lib/CodeGen/AtomicExpandPass.cpp
@@ -423,6 +423,9 @@ bool AtomicExpand::expandAtomicLoadToLL(LoadInst *LI) {
 bool AtomicExpand::expandAtomicLoadToCmpXchg(LoadInst *LI) {
   IRBuilder<> Builder(LI);
   AtomicOrdering Order = LI->getOrdering();
+  if (Order == AtomicOrdering::Unordered)
+    Order = AtomicOrdering::Monotonic;
+
   Value *Addr = LI->getPointerOperand();
   Type *Ty = cast<PointerType>(Addr->getType())->getElementType();
   Constant *DummyVal = Constant::getNullValue(Ty);