[NVPTX] Allow undef value as global initializer

Summary:
__shared__ variable may now emit undef value as initializer, do not
throw error on that.

Test Plan: test/CodeGen/NVPTX/global-addrspace.ll

Patch by Xuetian Weng

Reviewers: jholewinski, tra, jingyue

Subscribers: llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D12242

llvm-svn: 245785

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
index ffdac61f44d..16afe3cbfb5 100644
--- a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
@@ -1183,9 +1183,11 @@ void NVPTXAsmPrinter::printModuleLevelGV(const GlobalVariable *GVar,
           printScalarConstant(Initializer, O);
         }
       } else {
-        // The frontend adds zero-initializer to variables that don't have an
-        // initial value, so skip warning for this case.
-        if (!GVar->getInitializer()->isNullValue()) {
+        // The frontend adds zero-initializer to device and constant variables
+        // that don't have an initial value, and UndefValue to shared
+        // variables, so skip warning for this case.
+        if (!GVar->getInitializer()->isNullValue() &&
+            !isa<UndefValue>(GVar->getInitializer())) {
           report_fatal_error("initial value of '" + GVar->getName() +
                              "' is not allowed in addrspace(" +
                              Twine(PTy->getAddressSpace()) + ")");