Revert "[IRSim][IROutliner] Ignoring Musttail Function"

This reverts commit c7037c7257.

Pushed too soon

llvm/include/llvm/Analysis/IRSimilarityIdentifier.h

@@ -560,18 +560,6 @@ struct IRInstructionMapper {
         return Illegal;
       if (!F && !IsIndirectCall)
         return Illegal;
-      // Functions marked with the swifttailcc and tailcc calling conventions
-      // require special handling when outlining musttail functions.  The
-      // calling convention must be passed down to the outlined function as
-      // well. Further, there is special handling for musttail calls as well,
-      // requiring a return call directly after.  For now, the outliner does not
-      // support this, so we do not handle matching this case either.
-      if ((CI.getCallingConv() == CallingConv::SwiftTail ||
-           CI.getCallingConv() == CallingConv::Tail) &&
-          !EnableMustTailCalls)
-        return Illegal;
-      if (CI.isMustTailCall() && !EnableMustTailCalls)
-        return Illegal;
       return Legal;
     }
     // TODO: We do not current handle similarity that changes the control flow.
@@ -593,10 +581,6 @@ struct IRInstructionMapper {
     // Flag that lets the classifier know whether we should allow intrinsics to
     // be checked for similarity.
     bool EnableIntrinsics = false;
-  
-    // Flag that lets the classifier know whether we should allow tail calls to
-    // be checked for similarity.
-    bool EnableMustTailCalls = false;
   };
 
   /// Maps an Instruction to a member of InstrType.
@@ -984,13 +968,11 @@ public:
   IRSimilarityIdentifier(bool MatchBranches = true,
                          bool MatchIndirectCalls = true,
                          bool MatchCallsWithName = false,
-                         bool MatchIntrinsics = true,
-                         bool MatchMustTailCalls = true)
+                         bool MatchIntrinsics = true)
       : Mapper(&InstDataAllocator, &InstDataListAllocator),
         EnableBranches(MatchBranches), EnableIndirectCalls(MatchIndirectCalls),
         EnableMatchingCallsByName(MatchCallsWithName),
-        EnableIntrinsics(MatchIntrinsics),
-        EnableMustTailCalls(MatchMustTailCalls) {}
+        EnableIntrinsics(MatchIntrinsics) {}
 
 private:
   /// Map the instructions in the module to unsigned integers, using mapping
@@ -1083,10 +1065,6 @@ private:
   /// similarity.
   bool EnableIntrinsics = true;
 
-  // The flag variable that marks whether we should allow tailcalls
-  // to be checked for similarity.
-  bool EnableMustTailCalls = false;
-
   /// The SimilarityGroups found with the most recent run of \ref
   /// findSimilarity. None if there is no recent run.
   Optional<SimilarityGroupList> SimilarityCandidates;

llvm/include/llvm/Transforms/IPO/IROutliner.h

@@ -51,7 +51,6 @@
 struct OutlinableGroup;
 
 namespace llvm {
-using namespace CallingConv;
 using namespace IRSimilarity;
 
 class Module;
@@ -373,25 +372,6 @@ private:
       // the call in outlined functions.
       if (CI.canReturnTwice())
         return false;
-      // TODO: Update the outliner to capture whether the outlined function
-      // needs these extra attributes.
-
-      // Functions marked with the swifttailcc and tailcc calling conventions
-      // require special handling when outlining musttail functions.  The
-      // calling convention must be passed down to the outlined function as
-      // well. Further, there is special handling for musttail calls as well,
-      // requiring a return call directly after.  For now, the outliner does not
-      // support this.
-      bool IsTailCC = CI.getCallingConv() == CallingConv::SwiftTail ||
-                      CI.getCallingConv() == CallingConv::Tail;
-      if (IsTailCC && !EnableMustTailCalls)
-        return false;
-      if (CI.isMustTailCall() && !EnableMustTailCalls)
-        return false;
-      // The outliner can only handle musttail items if it is also accompanied
-      // by the tailcc or swifttailcc calling convention.
-      if (CI.isMustTailCall() && !IsTailCC)
-        return false;
       return true;
     }
     // TODO: Handle FreezeInsts.  Since a frozen value could be frozen inside
@@ -417,9 +397,6 @@ private:
     // The flag variable that marks whether we should allow intrinsics
     // instructions to be outlined.
     bool EnableIntrinsics = false;
-
-    // The flag variable that marks whether we should allow musttail calls.
-    bool EnableMustTailCalls = false;
   };
 
   /// A InstVisitor used to exclude certain instructions from being outlined.

llvm/lib/Analysis/IRSimilarityIdentifier.cpp

@@ -1163,7 +1163,6 @@ SimilarityGroupList &IRSimilarityIdentifier::findSimilarity(
   Mapper.InstClassifier.EnableIndirectCalls = EnableIndirectCalls;
   Mapper.EnableMatchCallsByName = EnableMatchingCallsByName;
   Mapper.InstClassifier.EnableIntrinsics = EnableIntrinsics;
-  Mapper.InstClassifier.EnableMustTailCalls = EnableMustTailCalls;
 
   populateMapper(Modules, InstrList, IntegerMapping);
   findCandidates(InstrList, IntegerMapping);
@@ -1177,7 +1176,6 @@ SimilarityGroupList &IRSimilarityIdentifier::findSimilarity(Module &M) {
   Mapper.InstClassifier.EnableIndirectCalls = EnableIndirectCalls;
   Mapper.EnableMatchCallsByName = EnableMatchingCallsByName;
   Mapper.InstClassifier.EnableIntrinsics = EnableIntrinsics;
-  Mapper.InstClassifier.EnableMustTailCalls = EnableMustTailCalls;
 
   std::vector<IRInstructionData *> InstrList;
   std::vector<unsigned> IntegerMapping;
@@ -1199,8 +1197,7 @@ IRSimilarityIdentifierWrapperPass::IRSimilarityIdentifierWrapperPass()
 
 bool IRSimilarityIdentifierWrapperPass::doInitialization(Module &M) {
   IRSI.reset(new IRSimilarityIdentifier(!DisableBranches, !DisableIndirectCalls,
-                                        MatchCallsByName, !DisableIntrinsics,
-                                        false));
+                                        MatchCallsByName, !DisableIntrinsics));
   return false;
 }
 
@@ -1218,8 +1215,7 @@ AnalysisKey IRSimilarityAnalysis::Key;
 IRSimilarityIdentifier IRSimilarityAnalysis::run(Module &M,
                                                  ModuleAnalysisManager &) {
   auto IRSI = IRSimilarityIdentifier(!DisableBranches, !DisableIndirectCalls,
-                                     MatchCallsByName, !DisableIntrinsics,
-                                     false);
+                                     MatchCallsByName, !DisableIntrinsics);
   IRSI.findSimilarity(M);
   return IRSI;
 }

llvm/test/Transforms/IROutliner/outlining-musttail.ll

@@ -1,34 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --include-generated-funcs
-; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost < %s | FileCheck %s
-
-; Check that we do not outline musttail when swifttaill cc or tailcc
-; is not present.
-
-declare void @musttail()
-
-define void @f1() {
-  %a = alloca i32, align 4
-  store i32 2, i32* %a, align 4
-  musttail call void @musttail()
-  ret void
-}
-
-define void @f2() {
-  %a = alloca i32, align 4
-  store i32 2, i32* %a, align 4
-  musttail call void @musttail()
-  ret void
-}
-; CHECK-LABEL: @f1(
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    store i32 2, i32* [[A]], align 4
-; CHECK-NEXT:    musttail call void @musttail()
-; CHECK-NEXT:    ret void
-;
-;
-; CHECK-LABEL: @f2(
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    store i32 2, i32* [[A]], align 4
-; CHECK-NEXT:    musttail call void @musttail()
-; CHECK-NEXT:    ret void
-;

llvm/test/Transforms/IROutliner/outlining-swifttailcc.ll

@@ -1,33 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --include-generated-funcs
-; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost < %s | FileCheck %s
-
-; Check that we do not outline musttail calls when swifttailcc is present.
-
-declare swifttailcc void @musttail()
-
-define swifttailcc void @f1() {
-  %a = alloca i32, align 4
-  store i32 2, i32* %a, align 4
-  musttail call swifttailcc void @musttail()
-  ret void
-}
-
-define swifttailcc void @f2() {
-  %a = alloca i32, align 4
-  store i32 2, i32* %a, align 4
-  musttail call swifttailcc void @musttail()
-  ret void
-}
-; CHECK-LABEL: @f1(
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    store i32 2, i32* [[A]], align 4
-; CHECK-NEXT:    musttail call swifttailcc void @musttail()
-; CHECK-NEXT:    ret void
-;
-;
-; CHECK-LABEL: @f2(
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    store i32 2, i32* [[A]], align 4
-; CHECK-NEXT:    musttail call swifttailcc void @musttail()
-; CHECK-NEXT:    ret void
-;

llvm/test/Transforms/IROutliner/outlining-tailcc.ll

@@ -1,33 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --include-generated-funcs
-; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost < %s | FileCheck %s
-
-; Check that we not do outline musttail calls when tailcc is present.
-
-declare tailcc void @musttail()
-
-define tailcc void @f1() {
-  %a = alloca i32, align 4
-  store i32 2, i32* %a, align 4
-  musttail call tailcc void @musttail()
-  ret void
-}
-
-define tailcc void @f2() {
-  %a = alloca i32, align 4
-  store i32 2, i32* %a, align 4
-  musttail call tailcc void @musttail()
-  ret void
-}
-; CHECK-LABEL: @f1(
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    store i32 2, i32* [[A]], align 4
-; CHECK-NEXT:    musttail call tailcc void @musttail()
-; CHECK-NEXT:    ret void
-;
-;
-; CHECK-LABEL: @f2(
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    store i32 2, i32* [[A]], align 4
-; CHECK-NEXT:    musttail call tailcc void @musttail()
-; CHECK-NEXT:    ret void
-;