CallGraph: Fix IgnoreAssumeLikeCalls option to Function::hasAddressTaken

[arsenm]

Summary

This was added in 29e2d9461a91b and likely never worked in a useful
way.

The test added for it fails when converted to opaque pointers, since
the lifetime intrinsic now directly uses the address. The code was
only trying to handle a user indirectly through a bitcast
instruction. That would never have been useful; a bitcast of a global
value would be folded to a ConstantExpr cast.

I also don't understand why it was special casing use_empty on the
cast. Relax the check to be either BitCastOperator or
AddrSpaceCastOperator. In practice, BitCastOperator won't appear
today.

I believe the change in parallel_deletion_cg_update is a correct
improvement but I didn't fully follow it. .omp_outlined..0 is used in
a constant expression cast to a call which ends up getting deleted.

[jdoerfert]

LG, makes sense to me

[madhur13490]

Looks fine

[rampitec]

LGTM. AFAIR user_empty() was guarding some failure with using iterator, which does not seem relevant anymore.

[arsenm]

0a67e771f6d21b1232c40f226c4eee48c3527210

llvm/lib/IR/Function.cpp

Optional<Function *> Intrinsic::remangleIntrinsicFunction(Function *F) {
   }();
 
   NewDecl->setCallingConv(F->getCallingConv());
   assert(NewDecl->getFunctionType() == F->getFunctionType() &&
          "Shouldn't change the signature");
   return NewDecl;
 }
 
+static bool isPointerCastOperator(const User *U) {
+  return isa<AddrSpaceCastOperator>(U) || isa<BitCastOperator>(U);
+}
+
 /// hasAddressTaken - returns true if there are any uses of this function
 /// other than direct calls or invokes to it. Optionally ignores callback
 /// uses, assume like pointer annotation calls, and references in llvm.used
 /// and llvm.compiler.used variables.
 bool Function::hasAddressTaken(const User **PutOffender,
                                bool IgnoreCallbackUses,
                                bool IgnoreAssumeLikeCalls, bool IgnoreLLVMUsed,
                                bool IgnoreARCAttachedCall) const {
   for (const Use &U : uses()) {
     const User *FU = U.getUser();
     if (isa<BlockAddress>(FU))
       continue;
 
     if (IgnoreCallbackUses) {
       AbstractCallSite ACS(&U);
       if (ACS && ACS.isCallbackCall())
         continue;
     }
 
     const auto *Call = dyn_cast<CallBase>(FU);
     if (!Call) {
-      if (IgnoreAssumeLikeCalls) {
-        if (const auto *FI = dyn_cast<Instruction>(FU)) {
-          if (FI->isCast() && !FI->user_empty() &&
-              llvm::all_of(FU->users(), [](const User *U) {
-                if (const auto *I = dyn_cast<IntrinsicInst>(U))
-                  return I->isAssumeLikeIntrinsic();
-                return false;
-              }))
-            continue;
-        }
-      }
+      if (IgnoreAssumeLikeCalls && isPointerCastOperator(FU) &&
+          all_of(FU->users(), [](const User *U) {
+          })) {
+
       if (IgnoreLLVMUsed && !FU->user_empty()) {
         const User *FUU = FU;
         if (isa<BitCastOperator>(FU) && FU->hasOneUse() &&
             !FU->user_begin()->user_empty())
           FUU = *FU->user_begin();
         if (llvm::all_of(FUU->users(), [](const User *U) {
               if (const auto *GV = dyn_cast<GlobalVariable>(U))
                 return GV->hasName() &&
                        (GV->getName().equals("llvm.compiler.used") ||
                         GV->getName().equals("llvm.used"));
               return false;
             }))
           continue;
       }
       if (PutOffender)
         *PutOffender = FU;
       return true;
     }
+
+    if (IgnoreAssumeLikeCalls) {
+      if (const auto *I = dyn_cast<IntrinsicInst>(Call))
+        if (I->isAssumeLikeIntrinsic())
+          continue;
+    }
+
     if (!Call->isCallee(&U) || Call->getFunctionType() != getFunctionType()) {
       if (IgnoreARCAttachedCall &&
           Call->isOperandBundleOfType(LLVMContext::OB_clang_arc_attachedcall,
                                       U.getOperandNo()))
         continue;
 
       if (PutOffender)
         *PutOffender = FU;

llvm/test/Analysis/CallGraph/ignore-assumelike-calls.ll

 ; RUN: opt < %s -print-callgraph -disable-output 2>&1 | FileCheck %s
 ; CHECK: Call graph node <<null function>><<{{.*}}>>  #uses=0
-; CHECK-NEXT:   CS<None> calls function 'cast_only'
-; CHECK-NEXT:   CS<None> calls function 'llvm.lifetime.start.p0i8'
+; CHECK-NEXT:   CS<None> calls function 'other_intrinsic_use'
+; CHECK-NEXT:   CS<None> calls function 'other_cast_intrinsic_use'
+; CHECK-NEXT:   CS<None> calls function 'llvm.lifetime.start.p0'
+; CHECK-NEXT:   CS<None> calls function 'llvm.memset.p0.i64'
+; CHECK-NEXT:   CS<None> calls function 'llvm.memset.p1.i64'
 ; CHECK-EMPTY:
-; CHECK-NEXT:   Call graph node for function: 'cast_only'<<{{.*}}>>  #uses=1
+; CHECK-NEXT:   Call graph node for function: 'addrspacecast_only'<<{{.*}}>>  #uses=0
 ; CHECK-EMPTY:
-; CHECK-NEXT:   Call graph node for function: 'llvm.lifetime.start.p0i8'<<{{.*}}>>  #uses=1
+; CHECK-NEXT:   Call graph node for function: 'bitcast_only'<<{{.*}}>>  #uses=0
+; CHECK-EMPTY:
+; CHECK-NEXT:   Call graph node for function: 'llvm.lifetime.start.p0'<<{{.*}}>>  #uses=1
+; CHECK-EMPTY:
+; CHECK-NEXT:   Call graph node for function: 'llvm.memset.p0.i64'<<{{.*}}>>  #uses=1
+; CHECK-EMPTY:
+; CHECK-NEXT:   Call graph node for function: 'llvm.memset.p1.i64'<<{{.*}}>>  #uses=1
+; CHECK-EMPTY:
+; CHECK-NEXT:   Call graph node for function: 'other_cast_intrinsic_use'<<{{.*}}>>  #uses=1
+; CHECK-EMPTY:
+; CHECK-NEXT:   Call graph node for function: 'other_intrinsic_use'<<{{.*}}>>  #uses=1
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   Call graph node for function: 'used_by_lifetime'<<{{.*}}>>  #uses=0
 ; CHECK-EMPTY:
+; CHECK-NEXT:   Call graph node for function: 'used_by_lifetime_cast'<<{{.*}}>>  #uses=0
+; CHECK-EMPTY:
 
 define internal void @used_by_lifetime() {
 entry:
-  %c = bitcast void()* @used_by_lifetime to i8*
-  call void @llvm.lifetime.start.p0i8(i64 4, i8* %c)
+  call void @llvm.lifetime.start.p0(i64 4, ptr @used_by_lifetime)
   ret void
 }
 
-define internal void @cast_only() {
+define internal void @used_by_lifetime_cast() addrspace(1) {
+  call void @llvm.lifetime.start.p0(i64 4, ptr addrspacecast (ptr addrspace(1) @used_by_lifetime_cast to ptr))
+  ret void
+}
+
+define internal void @bitcast_only() {
 entry:
-  %c = bitcast void()* @cast_only to i8*
+  %c = bitcast ptr @bitcast_only to ptr
+  ret void
+}
+
+define internal void @addrspacecast_only() addrspace(1) {
+entry:
+  %c = addrspacecast ptr addrspace(1) @addrspacecast_only to ptr
+  ret void
+}
+
+define internal void @other_intrinsic_use() {
+  call void @llvm.memset.p0.i64(ptr @other_intrinsic_use, i8 0, i64 1024, i1 false)
+  ret void
+}
+
+define internal void @other_cast_intrinsic_use() {
+  call void @llvm.memset.p1.i64(ptr addrspace(1) addrspacecast (ptr @other_cast_intrinsic_use to ptr addrspace(1)), i8 0, i64 1024, i1 false)
   ret void
 }
 
-declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture)
+declare void @llvm.lifetime.start.p0(i64, ptr nocapture)
+declare void @llvm.memset.p0.i64(ptr, i8, i64, i1 immarg)
+declare void @llvm.memset.p1.i64(ptr addrspace(1), i8, i64, i1 immarg)

llvm/test/Transforms/OpenMP/parallel_deletion_cg_update.ll

 ; RUN: opt < %s -passes='function(instcombine),cgscc(attributor-cgscc),print-callgraph' -disable-output 2>&1 | FileCheck %s
 
 ; CHECK: Call graph node <<null function>><<{{.*}}>>  #uses=0
-; CHECK:   CS<None> calls function 'dead_fork_call'
-; CHECK:   CS<None> calls function '.omp_outlined..0'
-; CHECK:   CS<None> calls function '__kmpc_fork_call'
-; CHECK:   CS<None> calls function 'live_fork_call'
-; CHECK:   CS<None> calls function '.omp_outlined..1'
-; CHECK:   CS<None> calls function 'd'
+; CHECK-NEXT:   CS<None> calls function 'dead_fork_call'
+; CHECK-NEXT:   CS<None> calls function '__kmpc_fork_call'
+; CHECK-NEXT:   CS<None> calls function 'live_fork_call'
+; CHECK-NEXT:   CS<None> calls function '.omp_outlined..1'
+; CHECK-NEXT:   CS<None> calls function 'd'
 ;
-; CHECK: Call graph node for function: '.omp_outlined..0'<<{{.*}}>>  #uses=1
-; 
+; CHECK: Call graph node for function: '.omp_outlined..0'<<{{.*}}>>  #uses=0
+;
 ; CHECK: Call graph node for function: '.omp_outlined..1'<<{{.*}}>>  #uses=3
 ; CHECK:   CS<{{.*}}> calls function 'd'
 ;
 ; CHECK: Call graph node for function: '__kmpc_fork_call'<<{{.*}}>>  #uses=3
 ; CHECK:   CS<None> calls external node
 ;
 ; CHECK: Call graph node for function: 'd'<<{{.*}}>>  #uses=2
 ; CHECK:   CS<None> calls external node