Use the new side effects in CSE

Author: eeckstein

lib/SILOptimizer/Transforms/CSE.cpp

@@ -27,8 +27,8 @@
 #include "swift/SIL/SILValue.h"
 #include "swift/SIL/SILVisitor.h"
 #include "swift/SILOptimizer/Analysis/ArraySemantic.h"
+#include "swift/SILOptimizer/Analysis/BasicCalleeAnalysis.h"
 #include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
-#include "swift/SILOptimizer/Analysis/SideEffectAnalysis.h"
 #include "swift/SILOptimizer/Analysis/SimplifyInstruction.h"
 #include "swift/SILOptimizer/PassManager/Passes.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
@@ -583,7 +583,7 @@ class CSE {
   /// their lookup.
   ScopedHTType *AvailableValues;
 
-  SideEffectAnalysis *SEA;
+  BasicCalleeAnalysis *BCA;
 
   SILOptFunctionBuilder &FuncBuilder;
 
@@ -595,10 +595,10 @@ class CSE {
   /// load of the property value.
   llvm::SmallVector<ApplyInst *, 8> lazyPropertyGetters;
 
-  CSE(bool RunsOnHighLevelSil, SideEffectAnalysis *SEA,
+  CSE(bool RunsOnHighLevelSil, BasicCalleeAnalysis *BCA,
       SILOptFunctionBuilder &FuncBuilder, DeadEndBlocks &DeadEndBBs,
       OwnershipFixupContext &RAUWFixupContext)
-      : SEA(SEA), FuncBuilder(FuncBuilder), DeadEndBBs(DeadEndBBs),
+      : BCA(BCA), FuncBuilder(FuncBuilder), DeadEndBBs(DeadEndBBs),
         RAUWFixupContext(RAUWFixupContext),
         RunsOnHighLevelSil(RunsOnHighLevelSil) {}
 
@@ -1064,16 +1064,22 @@ bool CSE::canHandle(SILInstruction *Inst) {
           return false;
       }
     }
-    
+
+    if (!AI->getFunction()->hasOwnership()) {
+      // In non-OSSA we don't balance CSE'd apply results which return an
+      // owned value.
+      if (auto ri = AI->getSingleResult()) {
+        if (ri.getValue().getConvention() != ResultConvention::Unowned)
+          return false;
+      }
+    }
+
     // We can CSE function calls which do not read or write memory and don't
     // have any other side effects.
-    FunctionSideEffects Effects;
-    SEA->getCalleeEffects(Effects, AI);
-
     // Note that the function also may not contain any retains. And there are
     // functions which are read-none and have a retain, e.g. functions which
     // _convert_ a global_addr to a reference and retain it.
-    auto MB = Effects.getMemBehavior(RetainObserveKind::ObserveRetains);
+    auto MB = BCA->getMemoryBehavior(ApplySite(AI), /*observeRetains*/false);
     if (MB == SILInstruction::MemoryBehavior::None)
       return true;
 
@@ -1392,14 +1398,14 @@ class SILCSE : public SILFunctionTransform {
 
     DominanceAnalysis* DA = getAnalysis<DominanceAnalysis>();
 
-    auto *SEA = PM->getAnalysis<SideEffectAnalysis>();
+    auto *BCA = PM->getAnalysis<BasicCalleeAnalysis>();
     SILOptFunctionBuilder FuncBuilder(*this);
 
     auto *Fn = getFunction();
     DeadEndBlocks DeadEndBBs(Fn);
     InstModCallbacks callbacks;
     OwnershipFixupContext FixupCtx{callbacks, DeadEndBBs};
-    CSE C(RunsOnHighLevelSil, SEA, FuncBuilder, DeadEndBBs, FixupCtx);
+    CSE C(RunsOnHighLevelSil, BCA, FuncBuilder, DeadEndBBs, FixupCtx);
     bool Changed = false;
 
     // Perform the traditional CSE.

test/SILOptimizer/cse_apply.sil

@@ -1,4 +1,6 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -cse | %FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -compute-side-effects -cse | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
 
 sil_stage canonical
 
@@ -72,7 +74,7 @@ class XX {
 
 sil_global @ggs : $Storage
 
-sil @retain_only : $@convention(thin) () -> XX {
+sil @retain_only : $@convention(thin) () -> @owned XX {
 bb0:
   %g = global_addr @ggs : $*Storage
   %a = address_to_pointer %g : $*Storage to $Builtin.RawPointer
@@ -130,9 +132,9 @@ bb0(%0 : $Int64):
 //CHECK: return
 sil @dont_cse_retain_only_apply : $@convention(thin) () -> () {
 bb0:
-  %f = function_ref @retain_only : $@convention(thin) () -> XX
-  %a1 = apply %f() : $@convention(thin) () -> XX
-  %a2 = apply %f() : $@convention(thin) () -> XX
+  %f = function_ref @retain_only : $@convention(thin) () -> @owned XX
+  %a1 = apply %f() : $@convention(thin) () -> @owned XX
+  %a2 = apply %f() : $@convention(thin) () -> @owned XX
   strong_release %a1 : $XX
   strong_release %a2 : $XX
   %r = tuple()

test/SILOptimizer/cse_apply_ossa.sil

@@ -1,4 +1,6 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -cse | %FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -compute-side-effects -cse | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
 
 sil_stage canonical