diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 0e382874dcf..7ec31657ec4 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1433,21 +1433,28 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB) {
       continue;
 
     HaveRewritablePHIs = true;
-
-    // Check for safety.
     ConstantExpr *CE = dyn_cast<ConstantExpr>(ThenV);
     if (!CE)
-      continue; // Known safe.
+      continue; // Known safe and cheap.
+
+    if (!isSafeToSpeculativelyExecute(CE))
+      return false;
+
+    // Don't speculate into a select with a constant select expression operand.
+    // FIXME: This should really be a cost metric, but our cost model doesn't
+    // accurately model the expense of select.
+    if (Operator::getOpcode(CE) == Instruction::Select)
+      return false;
 
     // An unfolded ConstantExpr could end up getting expanded into
     // Instructions. Don't speculate this and another instruction at
     // the same time.
+    // FIXME: This is strange because provided we haven't already hit the cost
+    // of 1, this code will speculate an arbitrary number of complex constant
+    // expression PHI nodes. Also, this doesn't account for how complex the
+    // constant expression is.
     if (SpeculationCost > 0)
       return false;
-    if (!isSafeToSpeculativelyExecute(CE))
-      return false;
-    if (ComputeSpeculationCost(CE) > PHINodeFoldingThreshold)
-      return false;
   }
 
   // If there are no PHIs to process, bail early. This helps ensure idempotence
diff --git a/test/Transforms/SimplifyCFG/SpeculativeExec.ll b/test/Transforms/SimplifyCFG/SpeculativeExec.ll
index a61867fe89c..c66d3ec67be 100644
--- a/test/Transforms/SimplifyCFG/SpeculativeExec.ll
+++ b/test/Transforms/SimplifyCFG/SpeculativeExec.ll
@@ -44,3 +44,25 @@ join:
   ret i8 %c
 }
 
+define i8* @test3(i1* %dummy, i8* %a, i8* %b) {
+; Test that a weird, unfolded constant cast in the PHI don't block speculation.
+; CHECK: @test3
+
+entry:
+  %cond1 = load volatile i1* %dummy
+  br i1 %cond1, label %if, label %end
+
+if:
+  %cond2 = load volatile i1* %dummy
+  br i1 %cond2, label %then, label %end
+
+then:
+  br label %end
+
+end:
+  %x = phi i8* [ %a, %entry ], [ %b, %if ], [ inttoptr (i64 42 to i8*), %then ]
+; CHECK-NOT: phi
+; CHECK: select i1 %cond2, i8* inttoptr
+
+  ret i8* %x
+}