Make tBX_RET and tBX_RET_vararg predicable.

The normal tBX instruction is predicable, so there's no reason the
pseudos for using it as a return shouldn't be. Gives us some nice code-gen
improvements as can be seen by the test changes. In particular, several
tests now have to disable if-conversion because it works too well and defeats
the test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134746 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMConstantIslandPass.cpp b/lib/Target/ARM/ARMConstantIslandPass.cpp
index 309caee..f45ebdc 100644
--- a/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -1538,7 +1538,10 @@
     if (MI->getOpcode() == ARM::tPOP_RET &&
         MI->getOperand(2).getReg() == ARM::PC &&
         MI->getNumExplicitOperands() == 3) {
-      BuildMI(MI->getParent(), MI->getDebugLoc(), TII->get(ARM::tBX_RET));
+      // Create the new insn and copy the predicate from the old.
+      BuildMI(MI->getParent(), MI->getDebugLoc(), TII->get(ARM::tBX_RET))
+        .addOperand(MI->getOperand(0))
+        .addOperand(MI->getOperand(1));
       MI->eraseFromParent();
       MadeChange = true;
     }