Merge pull request swiftlang#80990 from nate-chandler/rdar147586673

[OSSACanOwned] Don't dead-end extend if consumed.

Author: nate-chandler

include/swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h

@@ -261,7 +261,7 @@ class CanonicalizeOSSALifetime final {
   SILValue currentDef;
 
   /// Instructions beyond which liveness is not extended by destroy uses.
-  ArrayRef<SILInstruction *> currentLexicalLifetimeEnds;
+  ArrayRef<SILInstruction *> explicitLifetimeEnds;
 
   /// Original points in the CFG where the current value's lifetime is consumed
   /// or destroyed.  Each block either contains a consuming instruction (e.g.
@@ -368,7 +368,7 @@ class CanonicalizeOSSALifetime final {
     clear();
 
     currentDef = def;
-    currentLexicalLifetimeEnds = lexicalLifetimeEnds;
+    explicitLifetimeEnds = lexicalLifetimeEnds;
 
     liveness->initializeDiscoveredBlocks(&discoveredBlocks);
     liveness->initializeDef(getCurrentDef());
@@ -465,6 +465,16 @@ class CanonicalizeOSSALifetime final {
   UserRange getUsers() const { return liveness->getAllUsers(); }
 
 private:
+  bool endingLifetimeAtExplicitEnds() const {
+    return explicitLifetimeEnds.size() > 0;
+  }
+
+  bool respectsDeadEnds() const {
+    // TODO: OSSALifetimeCompletion: Once lifetimes are always complete, delete
+    //                               this method.
+    return !endingLifetimeAtExplicitEnds();
+  }
+
   bool respectsDeinitBarriers() const {
     if (!currentDef->isLexical())
       return false;

lib/SILOptimizer/Utils/CanonicalizeOSSALifetime.cpp

@@ -387,9 +387,9 @@ void CanonicalizeOSSALifetime::extendLivenessToDeadEnds() {
 
 void CanonicalizeOSSALifetime::extendLivenessToDeinitBarriers() {
   SmallVector<SILInstruction *, 8> ends;
-  if (currentLexicalLifetimeEnds.size() > 0) {
+  if (endingLifetimeAtExplicitEnds()) {
     visitExtendedUnconsumedBoundary(
-        currentLexicalLifetimeEnds,
+        explicitLifetimeEnds,
         [&ends](auto *instruction, auto lifetimeEnding) {
           instruction->visitSubsequentInstructions([&](auto *next) {
             ends.push_back(next);
@@ -1406,10 +1406,12 @@ bool CanonicalizeOSSALifetime::computeLiveness() {
     clear();
     return false;
   }
-  if (respectsDeinitBarriers()) {
-    extendLexicalLivenessToDeadEnds();
+  if (respectsDeadEnds()) {
+    if (respectsDeinitBarriers()) {
+      extendLexicalLivenessToDeadEnds();
+    }
+    extendLivenessToDeadEnds();
   }
-  extendLivenessToDeadEnds();
   if (respectsDeinitBarriers()) {
     extendLivenessToDeinitBarriers();
   }

test/Interpreter/consume_operator_kills_copyable_values.swift.gyb

@@ -176,6 +176,20 @@ func testNested2_${introducer}(_ c1: Bool, _ c2: Bool) {
   end([c1, c2])
 }
 
+// CHECK-LABEL: begin testDeadEnd_{{let|var}}(_:)(true)
+// CHECK:       hi
+// CHECK:       adios
+// CHECK:       barrier
+// CHECK-LABEL: end testDeadEnd_{{let|var}}(_:)(true)
+func testDeadEnd_${introducer}(_ condition: Bool) {
+  begin([condition])
+  ${introducer} x = X(0)
+  _ = consume x
+  guard condition else { fatalError() }
+  barrier()
+  end([condition])
+}
+
 func main_${introducer}() {
   simple_${introducer}()
   testLeft_${introducer}(true)
@@ -188,6 +202,7 @@ func main_${introducer}() {
   testNested2_${introducer}(false, true)
   testNested2_${introducer}(true, false)
   testNested2_${introducer}(true, true)
+  testDeadEnd_${introducer}(true)
 }
 
 % end