Optimizer: correctly handle bit-wise escaping values in OSSA canonicalization

We cannot compute the liverange of a value if it bit-wise escapes.
This fixes a mis-compile in copy-propagation which hoists a destroy_value over a use of the escaped value when lexical liveranges are disabled.
The test case is a simplified SIL sequence from the stdlib core where this problem shows up, because we build the stdlib core with disabled lexical liveranges.

Author: eeckstein

lib/SILOptimizer/Utils/OSSACanonicalizeOwned.cpp

@@ -203,11 +203,11 @@ bool OSSACanonicalizeOwned::computeCanonicalLiveness() {
       // escape. Is it legal to canonicalize ForwardingUnowned?
       case OperandOwnership::ForwardingUnowned:
       case OperandOwnership::PointerEscape:
+      case OperandOwnership::BitwiseEscape:
         LLVM_DEBUG(llvm::dbgs() << "      Value escaped! Giving up\n");
         return false;
       case OperandOwnership::InstantaneousUse:
       case OperandOwnership::UnownedInstantaneousUse:
-      case OperandOwnership::BitwiseEscape:
         liveness->updateForUse(user, /*lifetimeEnding*/ false);
         break;
       case OperandOwnership::ForwardingConsume:

test/SILOptimizer/copy_propagation_non_lexical.sil

@@ -0,0 +1,30 @@
+// RUN: %target-sil-opt -copy-propagation -enable-lexical-lifetimes=false %s | %FileCheck %s
+
+sil_stage canonical
+
+import Builtin
+import Swift
+import SwiftShims
+
+class C {}
+
+// CHECK-LABEL: sil [ossa] @bitwise_escape :
+// CHECK-NOT:     destroy_value
+// CHECK:         strong_copy_unmanaged_value
+// CHECK:         destroy_value
+// CHECK-LABEL: } // end sil function 'bitwise_escape'
+sil [ossa] @bitwise_escape : $@convention(thin) (@owned Builtin.BridgeObject) -> @owned C {
+bb0(%0 : @owned $Builtin.BridgeObject):
+  %1 = unchecked_trivial_bit_cast %0 to $UInt64
+  %2 = struct_extract %1, #UInt64._value
+  %3 = builtin "truncOrBitCast_Int64_Word"(%2) : $Builtin.Word
+  %4 = builtin "inttoptr_Word"(%3) : $Builtin.RawPointer
+  %5 = struct $UnsafeRawPointer (%4)
+  %6 = unchecked_trivial_bit_cast %5 to $Unmanaged<C>
+  %7 = struct_extract %6, #Unmanaged._value
+  %8 = strong_copy_unmanaged_value %7
+  destroy_value %0
+  return %8
+}
+
+