[IR] Take operand bundles into account for call argument readonly/writeonly

[nikic]

Summary

We currently only take operand bundle effects into account when querying the function-level memory attributes. However, I believe that we also need to do the same for parameter attributes. For example, a call with deopt bundle to a function with readnone parameter attribute cannot treat that parameter as readnone, because the deopt bundle may read it.

[nikic]

Update BasicAA test.

[jdoerfert]

LG, operand bundles should be taken into account here too.

llvm/lib/IR/Instructions.cpp

 }
 
 /// Determine whether the argument or parameter has the given attribute.
 bool CallBase::paramHasAttr(unsigned ArgNo, Attribute::AttrKind Kind) const {
   assert(ArgNo < arg_size() && "Param index out of bounds!");
 
   if (Attrs.hasParamAttr(ArgNo, Kind))
     return true;
-  if (const Function *F = getCalledFunction())
-    return F->getAttributes().hasParamAttr(ArgNo, Kind);
+
+  const Function *F = getCalledFunction();
+  if (!F)
+    return false;
+
+  if (!F->getAttributes().hasParamAttr(ArgNo, Kind))
     return false;
+
+  // Take into account mod/ref by operand bundles.
+  switch (Kind) {
+  case Attribute::ReadNone:
+    return !hasReadingOperandBundles() && !hasClobberingOperandBundles();
+  case Attribute::ReadOnly:
+    return !hasClobberingOperandBundles();
+  case Attribute::WriteOnly:
+    return !hasReadingOperandBundles();
+  default:
+    return true;
+  }
 }
 
 bool CallBase::hasFnAttrOnCalledFunction(Attribute::AttrKind Kind) const {
   Value *V = getCalledOperand();
   if (auto *CE = dyn_cast<ConstantExpr>(V))
     if (CE->getOpcode() == BitCast)
       V = CE->getOperand(0);
 

llvm/test/Transforms/FunctionAttrs/readattrs.ll

 
 exit:
   ret void
 }
 
 declare void @readnone_param(ptr nocapture readnone %p)
 declare void @readonly_param(ptr nocapture readonly %p)
 
+; FIXME: While this can't be readnone, this could be readonly.
 define void @op_bundle_readnone_deopt(ptr %p) {
 ; CHECK-LABEL: define {{[^@]+}}@op_bundle_readnone_deopt
-; CHECK-SAME: (ptr nocapture readnone [[P:%.*]]) {
+; CHECK-SAME: (ptr nocapture [[P:%.*]]) {
 ; CHECK-NEXT:    call void @readnone_param(ptr [[P]]) [ "deopt"() ]
 ; CHECK-NEXT:    ret void
 ;
   call void @readnone_param(ptr %p) ["deopt"()]
   ret void
 }
 
 define void @op_bundle_readnone_unknown(ptr %p) {
 ; CHECK-LABEL: define {{[^@]+}}@op_bundle_readnone_unknown
-; CHECK-SAME: (ptr nocapture readnone [[P:%.*]]) {
+; CHECK-SAME: (ptr nocapture [[P:%.*]]) {
 ; CHECK-NEXT:    call void @readnone_param(ptr [[P]]) [ "unknown"() ]
 ; CHECK-NEXT:    ret void
 ;
   call void @readnone_param(ptr %p) ["unknown"()]
   ret void
 }
 
 define void @op_bundle_readonly_deopt(ptr %p) {
 ; CHECK-LABEL: define {{[^@]+}}@op_bundle_readonly_deopt
 ; CHECK-SAME: (ptr nocapture readonly [[P:%.*]]) {
 ; CHECK-NEXT:    call void @readonly_param(ptr [[P]]) [ "deopt"() ]
 ; CHECK-NEXT:    ret void
 ;
   call void @readonly_param(ptr %p) ["deopt"()]
   ret void
 }
 
 define void @op_bundle_readonly_unknown(ptr %p) {
 ; CHECK-LABEL: define {{[^@]+}}@op_bundle_readonly_unknown
-; CHECK-SAME: (ptr nocapture readonly [[P:%.*]]) {
+; CHECK-SAME: (ptr nocapture [[P:%.*]]) {
 ; CHECK-NEXT:    call void @readonly_param(ptr [[P]]) [ "unknown"() ]
 ; CHECK-NEXT:    ret void
 ;
   call void @readonly_param(ptr %p) ["unknown"()]
   ret void
 }

llvm/test/Transforms/FunctionAttrs/writeonly.ll

 ; CHECK-NEXT:    ret void
 ;
   call void @direct3_callee(ptr %p) ["may-read-and-capture"(ptr %p)]
   ret void
 }
 
 define void @direct3c(ptr %p) {
 ; CHECK-LABEL: define {{[^@]+}}@direct3c
-; CHECK-SAME: (ptr nocapture writeonly [[P:%.*]]) {
+; CHECK-SAME: (ptr nocapture [[P:%.*]]) {
 ; CHECK-NEXT:    call void @direct3_callee(ptr [[P]]) [ "may-read"() ]
 ; CHECK-NEXT:    ret void
 ;
   call void @direct3_callee(ptr %p) ["may-read"()]
   ret void
 }
 
 define void @fptr_test1(ptr %p, ptr %f) {