[PATCH] [X86] Don't try to generate direct calls to TLS globals

[Michael Kuperstein]

Hi majnemer,

The Call lowering assumes that if it's a global, we want to emit a direct call.
This is correct for regular globals, but not for TLS ones.

http://reviews.llvm.org/D6862

Files:
  lib/Target/X86/X86ISelLowering.cpp
  test/CodeGen/X86/pr22103.ll

Index: test/CodeGen/X86/pr22103.ll
===================================================================
--- test/CodeGen/X86/pr22103.ll
+++ test/CodeGen/X86/pr22103.ll
@@ -0,0 +1,16 @@
+; RUN: llc < %s | FileCheck %s
+; Don't try to emit a direct call through a TLS global.
+; This fixes PR22103
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at a = external thread_local global i64
+
+; Function Attrs: nounwind
+define void @_Z1fv() {
+; CHECK-NOT: callq *$a
+entry:
+  call void bitcast (i64* @a to void ()*)()
+  ret void
+}
\ No newline at end of file
Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -3083,10 +3083,11 @@
     // through a register, since the call instruction's 32-bit
     // pc-relative offset may not be large enough to hold the whole
     // address.
-  } else if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
+  } else if (Callee->getOpcode() == ISD::GlobalAddress) {
     // If the callee is a GlobalAddress node (quite common, every direct call
     // is) turn it into a TargetGlobalAddress node so that legalize doesn't hack
     // it.
+    GlobalAddressSDNode* G = cast<GlobalAddressSDNode>(Callee);
 
     // We should use extra load for direct calls to dllimported functions in
     // non-JIT mode.

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