From: David Majnemer <david.majnemer@gmail.com>
Date: Thu, 26 Jun 2014 03:02:19 +0000 (+0000)
Subject: GlobalOpt: Don't optimize thread_local for initializers
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=29640bcb7d7738e7e611b0150b6ac57e2d2b723f;p=oota-llvm.git

GlobalOpt: Don't optimize thread_local for initializers

Folding a reference to a thread_local variable into another global
variable's initializer is very problematic, there is no relocation that
exists to represent such an access.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211762 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 75c1878f3fd..36c04f092bc 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1980,9 +1980,10 @@ isSimpleEnoughValueToCommit(Constant *C,
 static bool isSimpleEnoughValueToCommitHelper(Constant *C,
                                    SmallPtrSet<Constant*, 8> &SimpleConstants,
                                    const DataLayout *DL) {
-  // Simple global addresses are supported, do not allow dllimport globals.
+  // Simple global addresses are supported, do not allow dllimport or
+  // thread-local globals.
   if (auto *GV = dyn_cast<GlobalValue>(C))
-    return !GV->hasDLLImportStorageClass();
+    return !GV->hasDLLImportStorageClass() && !GV->isThreadLocal();
 
   // Simple integer, undef, constant aggregate zero, etc are all supported.
   if (C->getNumOperands() == 0 || isa<BlockAddress>(C))
diff --git a/test/Transforms/GlobalOpt/constantfold-initializers.ll b/test/Transforms/GlobalOpt/constantfold-initializers.ll
index 53e8465b5e6..8fc13304f15 100644
--- a/test/Transforms/GlobalOpt/constantfold-initializers.ll
+++ b/test/Transforms/GlobalOpt/constantfold-initializers.ll
@@ -72,9 +72,19 @@ entry:
   ret void
 }
 
+@threadlocalptr = global i32* null, align 4
+; CHECK: @threadlocalptr = global i32* null, align 4
+@threadlocalvar = external thread_local global i32
+define internal void @test5() {
+entry:
+  store i32* @threadlocalvar, i32** @threadlocalptr, align 4
+  ret void
+}
+
 @llvm.global_ctors = appending constant
-  [4 x { i32, void ()* }]
+  [5 x { i32, void ()* }]
   [{ i32, void ()* } { i32 65535, void ()* @test1 },
    { i32, void ()* } { i32 65535, void ()* @test2 },
    { i32, void ()* } { i32 65535, void ()* @test3 },
+   { i32, void ()* } { i32 65535, void ()* @test4 },
    { i32, void ()* } { i32 65535, void ()* @test4 }]