[VirtRegMap] Fix for PR17825. Do not ignore noreturn definitions when setting

isPhysRegUsed if the unwind information is required.
Indeed, the runtime may need a correct stack to be able to unwind the call.

llvm-svn: 194271

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/VirtRegMap.cpp b/llvm/lib/CodeGen/VirtRegMap.cpp
index 0a08608ecfc..e0aa4053987 100644
--- a/llvm/lib/CodeGen/VirtRegMap.cpp
+++ b/llvm/lib/CodeGen/VirtRegMap.cpp
@@ -285,7 +285,11 @@ void VirtRegRewriter::rewrite() {
           if (!MO.isGlobal())
             continue;
           const Function *Func = dyn_cast<Function>(MO.getGlobal());
-          if (!Func || !Func->hasFnAttribute(Attribute::NoReturn))
+          if (!Func || !Func->hasFnAttribute(Attribute::NoReturn) ||
+              // We need to keep correct unwind information
+              // even if the function will not return, since the
+              // runtime may need it.
+              !Func->hasFnAttribute(Attribute::NoUnwind))
             continue;
           NoReturnInsts.insert(MI);
           break;