Put memory(none) attribute instead of readnone (#1746)

Instead of creating readnone attributes on each parameter of
a function it's better to put just memory(none) which was recently
introduced.

See https://reviews.llvm.org/D135780

Co-authored by: Zou, Feng <[email protected]>

Signed-off-by: Sidorov, Dmitry <[email protected]>

Author: MrSidims

lib/SPIRV/SPIRVReader.cpp

@@ -4341,9 +4341,7 @@ Instruction *SPIRVToLLVM::transOCLBuiltinFromExtInst(SPIRVExtInst *BC,
     if (isFuncNoUnwind())
       F->addFnAttr(Attribute::NoUnwind);
     if (isFuncReadNone(UnmangledName))
-      for (llvm::Argument &Arg : F->args())
-        if (Arg.getType()->isPointerTy())
-          Arg.addAttr(Attribute::ReadNone);
+      F->setDoesNotAccessMemory();
   }
   auto Args = transValue(BC->getArgValues(), F, BB);
   SPIRVDBG(dbgs() << "[transOCLBuiltinFromExtInst] Function: " << *F

lib/SPIRV/SPIRVUtil.cpp

@@ -1931,9 +1931,7 @@ bool lowerBuiltinVariableToCall(GlobalVariable *GV,
     Func->setCallingConv(CallingConv::SPIR_FUNC);
     Func->addFnAttr(Attribute::NoUnwind);
     Func->addFnAttr(Attribute::WillReturn);
-    for (llvm::Argument &Arg : Func->args())
-      if (Arg.getType()->isPointerTy())
-        Arg.addAttr(Attribute::ReadNone);
+    Func->setDoesNotAccessMemory();
   }
 
   // Collect instructions in these containers to remove them later.

test/transcoding/builtin_vars_arithmetics.ll

@@ -123,7 +123,7 @@ entry:
 
 attributes #0 = { norecurse "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "sycl-module-id"="test.cpp" "uniform-work-group-size"="true" "unsafe-fp-math"="false" "use-soft-float"="false" }
 
-; CHECK-LLVM-OCL: attributes #1 = { nounwind willreturn }
+; CHECK-LLVM-OCL: attributes #1 = { nounwind willreturn memory(none) }
 
 !llvm.module.flags = !{!0}
 !opencl.spir.version = !{!1}