Merging r309594:

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r309594 | majnemer | 2017-07-31 10:47:07 -0700 (Mon, 31 Jul 2017) | 4 lines

[IPSCCP] Guard a user of getInitializer with hasDefinitiveInitializer

We are not allowed to reason about an initializer value without first
consulting hasDefinitiveInitializer.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_50@309827 91177308-0d34-0410-b5e6-96231b3b80d8

Author: zmodem

lib/Transforms/Scalar/SCCP.cpp

@@ -1790,7 +1790,8 @@ static bool runIPSCCP(Module &M, const DataLayout &DL,
   // variables that do not have their 'addresses taken'.  If they don't have
   // their addresses taken, we can propagate constants through them.
   for (GlobalVariable &G : M.globals())
-    if (!G.isConstant() && G.hasLocalLinkage() && !AddressIsTaken(&G))
+    if (!G.isConstant() && G.hasLocalLinkage() &&
+        G.hasDefinitiveInitializer() && !AddressIsTaken(&G))
       Solver.TrackValueOfGlobalVariable(&G);
 
   // Solve for constants.

test/Transforms/SCCP/definite-initializer.ll

@@ -0,0 +1,11 @@
+; RUN: opt -S -ipsccp < %s | FileCheck %s
+@d = internal externally_initialized global i32 0, section ".openbsd.randomdata", align 4
+
+; CHECK-LABEL: @test1(
+define i32 @test1() {
+entry:
+  %load = load i32, i32* @d, align 4
+  ret i32 %load
+; CHECK: %[[load:.*]] = load i32, i32* @d, align 4
+; CHECK: ret i32 %[[load]]
+}