4 files changed, 28 insertions, 21 deletions
diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index 3c0e7ae799f..0cd9b88ea92 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -991,31 +991,32 @@ static bool setDoesNotRecurse(Function &F) {
   return true;
 }
 
-static bool addNoRecurseAttrs(const CallGraphSCC &SCC) {
+static bool addNoRecurseAttrs(const SCCNodeSet &SCCNodes) {
   // Try and identify functions that do not recurse.
 
   // If the SCC contains multiple nodes we know for sure there is recursion.
-  if (!SCC.isSingular())
+  if (SCCNodes.size() != 1)
     return false;
 
-  const CallGraphNode *CGN = *SCC.begin();
-  Function *F = CGN->getFunction();
+  Function *F = *SCCNodes.begin();
   if (!F || F->isDeclaration() || F->doesNotRecurse())
     return false;
 
   // If all of the calls in F are identifiable and are to norecurse functions, F
   // is norecurse. This check also detects self-recursion as F is not currently
   // marked norecurse, so any called from F to F will not be marked norecurse.
-  if (std::all_of(CGN->begin(), CGN->end(),
-                  [](const CallGraphNode::CallRecord &CR) {
-                    Function *F = CR.second->getFunction();
-                    return F && F->doesNotRecurse();
-                  }))
-    // Function calls a potentially recursive function.
-    return setDoesNotRecurse(*F);
-
-  // Nothing else we can deduce usefully during the postorder traversal.
-  return false;
+  for (Instruction &I : instructions(*F))
+    if (auto CS = CallSite(&I)) {
+      Function *Callee = CS.getCalledFunction();
+      if (!Callee || Callee == F || !Callee->doesNotRecurse())
+        // Function calls a potentially recursive function.
+        return false;
+    }
+
+  // Every call was to a non-recursive function other than this function, and
+  // we have no indirect recursion as the SCC size is one. This function cannot
+  // recurse.
+  return setDoesNotRecurse(*F);
 }
 
 bool PostOrderFunctionAttrs::runOnSCC(CallGraphSCC &SCC) {
@@ -1060,9 +1061,9 @@ bool PostOrderFunctionAttrs::runOnSCC(CallGraphSCC &SCC) {
     Changed |= addNoAliasAttrs(SCCNodes);
     Changed |= addNonNullAttrs(SCCNodes, *TLI);
     Changed |= removeConvergentAttrs(SCCNodes);
+    Changed |= addNoRecurseAttrs(SCCNodes);
   }
 
-  Changed |= addNoRecurseAttrs(SCC);
   return Changed;
 }
 
diff --git a/llvm/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll b/llvm/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
index fe2fdd74b41..ed091466165 100644
--- a/llvm/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
+++ b/llvm/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
@@ -43,13 +43,13 @@ define void @test1_no(i32* %p) nounwind {
 ; This is unusual, since the function is memcpy, but as above, this
 ; isn't necessarily invalid.
 
-; CHECK: define void @test2_yes(i8* nocapture %p, i8* nocapture %q, i64 %n) #0 {
+; CHECK: define void @test2_yes(i8* nocapture %p, i8* nocapture %q, i64 %n) #4 {
 define void @test2_yes(i8* %p, i8* %q, i64 %n) nounwind {
   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %p, i8* %q, i64 %n, i32 1, i1 false), !tbaa !1
   ret void
 }
 
-; CHECK: define void @test2_no(i8* nocapture %p, i8* nocapture readonly %q, i64 %n) #1 {
+; CHECK: define void @test2_no(i8* nocapture %p, i8* nocapture readonly %q, i64 %n) #3 {
 define void @test2_no(i8* %p, i8* %q, i64 %n) nounwind {
   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %p, i8* %q, i64 %n, i32 1, i1 false), !tbaa !2
   ret void
@@ -76,7 +76,8 @@ declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i32, i1) nounwind
 ; CHECK: attributes #1 = { norecurse nounwind }
 ; CHECK: attributes #2 = { nounwind readonly }
 ; CHECK: attributes #3 = { nounwind }
-; CHECK: attributes #4 = { argmemonly nounwind }
+; CHECK: attributes #4 = { nounwind readnone }
+; CHECK: attributes #5 = { argmemonly nounwind }
 
 ; Root note.
 !0 = !{ }
diff --git a/llvm/test/Transforms/FunctionAttrs/norecurse.ll b/llvm/test/Transforms/FunctionAttrs/norecurse.ll
index d5a2d820840..221b539655a 100644
--- a/llvm/test/Transforms/FunctionAttrs/norecurse.ll
+++ b/llvm/test/Transforms/FunctionAttrs/norecurse.ll
@@ -29,6 +29,13 @@ define i32 @extern() {
 }
 declare i32 @k() readnone
 
+; CHECK: define void @intrinsic(i8* nocapture %dest, i8* nocapture readonly %src, i32 %len) {
+define void @intrinsic(i8* %dest, i8* %src, i32 %len) {
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 %len, i32 1, i1 false)
+  ret void
+}
+declare void @llvm.memcpy.p0i8.p0i8.i32(i8*, i8*, i32, i32, i1)
+
 ; CHECK: define internal i32 @called_by_norecurse() #0
 define internal i32 @called_by_norecurse() {
   %a = call i32 @k()
diff --git a/llvm/test/Transforms/FunctionAttrs/optnone.ll b/llvm/test/Transforms/FunctionAttrs/optnone.ll
index 441ff4da65e..cd08c75d75b 100644
--- a/llvm/test/Transforms/FunctionAttrs/optnone.ll
+++ b/llvm/test/Transforms/FunctionAttrs/optnone.ll
@@ -16,11 +16,9 @@ define void @test_optnone(i8* %p) noinline optnone {
 
 declare i8 @strlen(i8*) noinline optnone
 ; CHECK-LABEL: @strlen
-; CHECK: (i8*) #2
+; CHECK: (i8*) #1
 
 ; CHECK-LABEL: attributes #0
 ; CHECK: = { norecurse readnone }
 ; CHECK-LABEL: attributes #1
-; CHECK: = { noinline norecurse optnone }
-; CHECK-LABEL: attributes #2
 ; CHECK: = { noinline optnone }