Don't build switch tables for dllimport and TLS variables in GEPs

This is a follow-up to r211331, which failed to notice that we were
returning early from ValidLookupTableConstant for GEPs.

llvm-svn: 211753

2 files changed, 11 insertions, 7 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index ff2f2a03622..b1f9bff5377 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -3311,13 +3311,14 @@ static bool ForwardSwitchConditionToPHI(SwitchInst *SI) {
 /// ValidLookupTableConstant - Return true if the backend will be able to handle
 /// initializing an array of constants like C.
 static bool ValidLookupTableConstant(Constant *C) {
-  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
-    return CE->isGEPWithNoNotionalOverIndexing();
   if (C->isThreadDependent())
     return false;
   if (C->isDLLImportDependent())
     return false;
 
+  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
+    return CE->isGEPWithNoNotionalOverIndexing();
+
   return isa<ConstantFP>(C) ||
       isa<ConstantInt>(C) ||
       isa<ConstantPointerNull>(C) ||
diff --git a/llvm/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll b/llvm/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll
index ee63d2c0c0f..51ced4099ac 100644
--- a/llvm/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll
+++ b/llvm/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll
@@ -946,10 +946,10 @@ return:
 }
 
 ; Don't build tables for switches with dllimport variables.
-@dllimport_a = external dllimport global i32
-@dllimport_b = external dllimport global i32
-@dllimport_c = external dllimport global i32
-@dllimport_d = external dllimport global i32
+@dllimport_a = external dllimport global [3x i32]
+@dllimport_b = external dllimport global [3x i32]
+@dllimport_c = external dllimport global [3x i32]
+@dllimport_d = external dllimport global [3x i32]
 define i32* @dllimport(i32 %x) {
 entry:
   switch i32 %x, label %sw.default [
@@ -964,7 +964,10 @@ sw.bb2:
 sw.default:
   br label %return
 return:
-  %retval.0 = phi i32* [ @dllimport_d, %sw.default ], [ @dllimport_c, %sw.bb2 ], [ @dllimport_b, %sw.bb1 ], [ @dllimport_a, %entry ]
+  %retval.0 = phi i32* [ getelementptr inbounds ([3 x i32]* @dllimport_d, i32 0, i32 0), %sw.default ],
+                       [ getelementptr inbounds ([3 x i32]* @dllimport_c, i32 0, i32 0), %sw.bb2 ],
+                       [ getelementptr inbounds ([3 x i32]* @dllimport_b, i32 0, i32 0), %sw.bb1 ],
+                       [ getelementptr inbounds ([3 x i32]* @dllimport_a, i32 0, i32 0), %entry ]
   ret i32* %retval.0
 ; CHECK-LABEL: @dllimport(
 ; CHECK: switch i32