Revert r275678, "Revert "Revert r275027 - Let FuncAttrs infer the 'returned' argument attribute""

This reverts also r275029, "Update Clang tests after adding inference for the returned argument attribute"

It broke LTO build. Seems miscompilation.

llvm-svn: 275756

clang/test/CodeGen/ppc64-struct-onevect.c

@@ -9,5 +9,5 @@ v4sf foo (struct s a) {
   return a.v;
 }
 
-// CHECK-LABEL: define <4 x float> @foo(<4 x float> inreg returned %a.coerce)
+// CHECK-LABEL: define <4 x float> @foo(<4 x float> inreg %a.coerce)
 // CHECK: ret <4 x float> %a.coerce

clang/test/CodeGenCXX/wasm-args-returns.cpp

@@ -14,7 +14,7 @@
 
 struct one_field { double d; };
 test(one_field);
-// CHECK: define double @_Z7forward9one_field(double returned %{{.*}})
+// CHECK: define double @_Z7forward9one_field(double %{{.*}})
 //
 // CHECK: define void @_Z14test_one_fieldv()
 // CHECK: %[[call:.*]] = tail call double @_Z13def_one_fieldv()
@@ -89,7 +89,7 @@ struct one_bitfield {
     int d:3;
 };
 test(one_bitfield);
-// CHECK: define i32 @_Z7forward12one_bitfield(i32 returned %{{.*}})
+// CHECK: define i32 @_Z7forward12one_bitfield(i32 %{{.*}})
 //
 // CHECK: define void @_Z17test_one_bitfieldv()
 // CHECK: %[[call:.*]] = tail call i32 @_Z16def_one_bitfieldv()

clang/test/CodeGenOpenCL/as_type.cl

@@ -51,7 +51,7 @@ int f6(char4 x) {
   return __builtin_astype(x, int);
 }
 
-//CHECK: define spir_func <3 x i8> @f7(<3 x i8> returned %[[x:.*]])
+//CHECK: define spir_func <3 x i8> @f7(<3 x i8> %[[x:.*]])
 //CHECK-NOT: bitcast
 //CHECK-NOT: shufflevector
 //CHECK: ret <3 x i8> %[[x]]

llvm/lib/Transforms/IPO/FunctionAttrs.cpp

@@ -42,7 +42,6 @@ using namespace llvm;
 STATISTIC(NumReadNone, "Number of functions marked readnone");
 STATISTIC(NumReadOnly, "Number of functions marked readonly");
 STATISTIC(NumNoCapture, "Number of arguments marked nocapture");
-STATISTIC(NumReturned, "Number of arguments marked returned");
 STATISTIC(NumReadNoneArg, "Number of arguments marked readnone");
 STATISTIC(NumReadOnlyArg, "Number of arguments marked readonly");
 STATISTIC(NumNoAlias, "Number of function returns marked noalias");
@@ -484,53 +483,6 @@ determinePointerReadAttrs(Argument *A,
   return IsRead ? Attribute::ReadOnly : Attribute::ReadNone;
 }
 
-/// Deduce returned attributes for the SCC.
-static bool addArgumentReturnedAttrs(const SCCNodeSet &SCCNodes) {
-  bool Changed = false;
-
-  AttrBuilder B;
-  B.addAttribute(Attribute::Returned);
-
-  // Check each function in turn, determining if an argument is always returned.
-  for (Function *F : SCCNodes) {
-    // We can infer and propagate function attributes only when we know that the
-    // definition we'll get at link time is *exactly* the definition we see now.
-    // For more details, see GlobalValue::mayBeDerefined.
-    if (!F->hasExactDefinition())
-      continue;
-
-    if (F->getReturnType()->isVoidTy())
-      continue;
-
-    auto FindRetArg = [&]() -> Value * {
-      Value *RetArg = nullptr;
-      for (BasicBlock &BB : *F)
-        if (auto *Ret = dyn_cast<ReturnInst>(BB.getTerminator())) {
-          // Note that stripPointerCasts should look through functions with
-          // returned arguments.
-          Value *RetVal = Ret->getReturnValue()->stripPointerCasts();
-          if (RetVal->getType() == F->getReturnType() && isa<Argument>(RetVal)) {
-            if (!RetArg)
-              RetArg = RetVal;
-            else if (RetArg != RetVal)
-              return nullptr;
-          }
-        }
-
-      return RetArg;
-    };
-
-    if (Value *RetArg = FindRetArg()) {
-      auto *A = cast<Argument>(RetArg);
-      A->addAttr(AttributeSet::get(F->getContext(), A->getArgNo() + 1, B));
-      ++NumReturned;
-      Changed = true;
-    }
-  }
-
-  return Changed;
-}
-
 /// Deduce nocapture attributes for the SCC.
 static bool addArgumentAttrs(const SCCNodeSet &SCCNodes) {
   bool Changed = false;
@@ -1072,7 +1024,6 @@ PreservedAnalyses PostOrderFunctionAttrsPass::run(LazyCallGraph::SCC &C,
   }
 
   bool Changed = false;
-  Changed |= addArgumentReturnedAttrs(SCCNodes);
   Changed |= addReadAttrs(SCCNodes, AARGetter);
   Changed |= addArgumentAttrs(SCCNodes);
 
@@ -1138,7 +1089,6 @@ static bool runImpl(CallGraphSCC &SCC, AARGetterT AARGetter) {
     SCCNodes.insert(F);
   }
 
-  Changed |= addArgumentReturnedAttrs(SCCNodes);
   Changed |= addReadAttrs(SCCNodes, AARGetter);
   Changed |= addArgumentAttrs(SCCNodes);
 

llvm/test/Transforms/FunctionAttrs/2009-01-02-LocalStores.ll

@@ -14,7 +14,7 @@ define i32* @b(i32 *%q) {
 	ret i32* %tmp
 }
 
-; CHECK: define i32* @c(i32* readnone returned %r)
+; CHECK: define i32* @c(i32* readnone %r)
 @g = global i32 0
 define i32* @c(i32 *%r) {
 	%a = icmp eq i32* %r, null

llvm/test/Transforms/FunctionAttrs/nocapture.ll

@@ -1,7 +1,7 @@
 ; RUN: opt < %s -functionattrs -S | FileCheck %s
 @g = global i32* null		; <i32**> [#uses=1]
 
-; CHECK: define i32* @c1(i32* readnone returned %q)
+; CHECK: define i32* @c1(i32* readnone %q)
 define i32* @c1(i32* %q) {
 	ret i32* %q
 }
@@ -140,7 +140,7 @@ define void @test1_1(i8* %x1_1, i8* %y1_1) {
   ret void
 }
 
-; CHECK: define i8* @test1_2(i8* nocapture readnone %x1_2, i8* returned %y1_2)
+; CHECK: define i8* @test1_2(i8* nocapture readnone %x1_2, i8* %y1_2)
 define i8* @test1_2(i8* %x1_2, i8* %y1_2) {
   call void @test1_1(i8* %x1_2, i8* %y1_2)
   store i32* null, i32** @g
@@ -168,7 +168,7 @@ define void @test4_1(i8* %x4_1) {
   ret void
 }
 
-; CHECK: define i8* @test4_2(i8* nocapture readnone %x4_2, i8* readnone returned %y4_2, i8* nocapture readnone %z4_2)
+; CHECK: define i8* @test4_2(i8* nocapture readnone %x4_2, i8* readnone %y4_2, i8* nocapture readnone %z4_2)
 define i8* @test4_2(i8* %x4_2, i8* %y4_2, i8* %z4_2) {
   call void @test4_1(i8* null)
   store i32* null, i32** @g

llvm/test/Transforms/FunctionAttrs/readattrs.ll

@@ -11,7 +11,7 @@ define void @test1_2(i8* %x1_2, i8* %y1_2, i8* %z1_2) {
   ret void
 }
 
-; CHECK: define i8* @test2(i8* readnone returned %p)
+; CHECK: define i8* @test2(i8* readnone %p)
 define i8* @test2(i8* %p) {
   store i32 0, i32* @x
   ret i8* %p
@@ -53,7 +53,7 @@ define void @test7_1(i32* inalloca %a) {
   ret void
 }
 
-; CHECK: define i32* @test8_1(i32* readnone returned %p)
+; CHECK: define i32* @test8_1(i32* readnone %p)
 define i32* @test8_1(i32* %p) {
 entry:
   ret i32* %p