---

yaml
---
r: 319399
b: refs/heads/master-rebranch
c: fef9eea
h: refs/heads/master
i:
  319397: 540d38b
  319395: a609752
  319391: be1ea5e

Author: swift-ci

[refs]

@@ -1457,4 +1457,4 @@ refs/tags/swift-DEVELOPMENT-SNAPSHOT-2019-08-02-a: ddd2b2976aa9bfde5f20fe37f6bd2
 refs/tags/swift-DEVELOPMENT-SNAPSHOT-2019-08-03-a: 171cc166f2abeb5ca2a4003700a8a78a108bd300
 refs/heads/benlangmuir-patch-1: baaebaf39d52f3bf36710d4fe40cf212e996b212
 refs/heads/i-do-redeclare: 8c4e6d5de5c1e3f0a2cedccf319df713ea22c48e
-refs/heads/master-rebranch: 9e87e491c68a514f48741d9ba249f677ef83eace
+refs/heads/master-rebranch: fef9eeab4a8f64f91ece7261fd3f4a629e2abd5b

branches/master-rebranch/lib/SILOptimizer/Utils/ConstExpr.cpp

@@ -406,6 +406,11 @@ SymbolicValue ConstExprFunctionState::computeConstantValue(SILValue value) {
   if (auto *bai = dyn_cast<BeginAccessInst>(value))
     return getConstantValue(bai->getOperand());
 
+  // Look through copy_value and begin_borrow since the interpreter doesn't
+  // model these memory management instructions.
+  if (isa<CopyValueInst>(value) || isa<BeginBorrowInst>(value))
+    return getConstantValue(cast<SingleValueInstruction>(value)->getOperand(0));
+
   LLVM_DEBUG(llvm::dbgs() << "ConstExpr Unknown simple: " << *value << "\n");
 
   // Otherwise, we don't know how to handle this.
@@ -1292,7 +1297,8 @@ ConstExprFunctionState::evaluateFlowSensitive(SILInstruction *inst) {
       // skip them.
       isa<DestroyAddrInst>(inst) || isa<RetainValueInst>(inst) ||
       isa<ReleaseValueInst>(inst) || isa<StrongRetainInst>(inst) ||
-      isa<StrongReleaseInst>(inst))
+      isa<StrongReleaseInst>(inst) || isa<DestroyValueInst>(inst) ||
+      isa<EndBorrowInst>(inst))
     return None;
 
   // If this is a special flow-sensitive instruction like a stack allocation,
@@ -1302,6 +1308,15 @@ ConstExprFunctionState::evaluateFlowSensitive(SILInstruction *inst) {
     return None;
   }
 
+  // Make sure that our copy_value, begin_borrow form constants. Otherwise,
+  // return why.
+  if (isa<CopyValueInst>(inst) || isa<BeginBorrowInst>(inst)) {
+    auto result = getConstantValue(inst->getOperand(0));
+    if (!result.isConstant())
+      return result;
+    return None;
+  }
+
   // If this is a deallocation of a memory object that we are tracking, then
   // don't do anything.  The memory is allocated in a BumpPtrAllocator so there
   // is no useful way to free it.