Merge pull request #86040 from eeckstein/fix-silcombine-6.3

[6.3] SILCombine: don't sink forwarding instructions with address operands

Author: eeckstein

lib/SILOptimizer/SILCombiner/SILCombine.cpp

@@ -429,6 +429,14 @@ bool SILCombiner::doOneIteration(SILFunction &F, unsigned Iteration) {
   return MadeChange;
 }
 
+static bool hasAddressOperands(SILInstruction *inst) {
+  for (Operand *op : inst->getRealOperands()) {
+    if (op->get()->getType().isAddress())
+      return true;
+  }
+  return false;
+}
+
 void SILCombiner::processInstruction(SILInstruction *I,
                                      SILCombineCanonicalize &scCanonicalize,
                                      bool &MadeChange) {
@@ -467,6 +475,15 @@ void SILCombiner::processInstruction(SILInstruction *I,
     if (auto *svi = dyn_cast<SingleValueInstruction>(I)) {
       if (auto fwdOp = ForwardingOperation(svi)) {
         if (fwdOp.getSingleForwardingOperand() &&
+
+            // Don't risk sinking instructions with address operands out of the
+            // addressed memory's lifetime. E.g:
+            // ```
+            //   %3 = mark_dependence %2 on %1 : $*T  // must not be moved after the destroy_addr
+            //   destroy_addr %1
+            // ```
+            !hasAddressOperands(svi) &&
+
             SILValue(svi)->getOwnershipKind() == OwnershipKind::Owned) {
           // Try to sink the value. If we sank the value and deleted it,
           // return. If we didn't optimize or sank but we are still able to

test/SILOptimizer/sil_combine_ossa.sil

@@ -5577,4 +5577,24 @@ bb0(%0 : @guaranteed $String):
   return %1
 }
 
+// CHECK-LABEL: sil [ossa] @dont_sink_mark_dependence_out_of_memory_lifetime :
+// CHECK:         mark_dependence
+// CHECK:       bb1:
+// CHECK:       } // end sil function 'dont_sink_mark_dependence_out_of_memory_lifetime'
+sil [ossa] @dont_sink_mark_dependence_out_of_memory_lifetime : $@convention(thin) (@owned Klass, @owned Klass) -> () {
+bb0(%0 : @owned $Klass, %1 : @owned $Klass):
+  %2 = alloc_stack $Klass
+  store %1 to [init] %2
+  %4 = mark_dependence %0 on %2
+  destroy_addr %2
+  br bb1
+
+bb1:
+  destroy_value %4
+  dealloc_stack %2
+  %9 = tuple ()
+  return %9
+}
+
+