[AMDGPU] Make getAssumedAddrSpace return AS1 for pointer kernel arguments

Author: shiltian

llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp

@@ -955,6 +955,10 @@ bool AMDGPUTargetMachine::isNoopAddrSpaceCast(unsigned SrcAS,
 }
 
 unsigned AMDGPUTargetMachine::getAssumedAddrSpace(const Value *V) const {
+  if (auto *Arg = dyn_cast<Argument>(V);
+      Arg && AMDGPU::isKernelCC(Arg->getParent()) && !Arg->hasByRefAttr())
+    return AMDGPUAS::GLOBAL_ADDRESS;
+
   const auto *LD = dyn_cast<LoadInst>(V);
   if (!LD) // TODO: Handle invariant load like constant.
     return AMDGPUAS::UNKNOWN_ADDRESS_SPACE;

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

@@ -12593,29 +12593,18 @@ struct AAAddressSpaceImpl : public AAAddressSpace {
   }
 
   ChangeStatus updateImpl(Attributor &A) override {
-    unsigned FlatAS = A.getInfoCache().getFlatAddressSpace().value();
     uint32_t OldAddressSpace = AssumedAddressSpace;
 
     auto CheckAddressSpace = [&](Value &Obj) {
       if (isa<UndefValue>(&Obj))
         return true;
-      // If an argument in flat address space only has addrspace cast uses, and
-      // those casts are same, then we take the dst addrspace.
       if (auto *Arg = dyn_cast<Argument>(&Obj)) {
-        if (Arg->getType()->getPointerAddressSpace() == FlatAS) {
-          unsigned CastAddrSpace = FlatAS;
-          for (auto *U : Arg->users()) {
-            auto *ASCI = dyn_cast<AddrSpaceCastInst>(U);
-            if (!ASCI)
-              return takeAddressSpace(Obj.getType()->getPointerAddressSpace());
-            if (CastAddrSpace != FlatAS &&
-                CastAddrSpace != ASCI->getDestAddressSpace())
-              return false;
-            CastAddrSpace = ASCI->getDestAddressSpace();
-          }
-          if (CastAddrSpace != FlatAS)
-            return takeAddressSpace(CastAddrSpace);
-        }
+        auto *TTI =
+            A.getInfoCache().getAnalysisResultForFunction<TargetIRAnalysis>(
+                *Arg->getParent());
+        unsigned AssumedAS = TTI->getAssumedAddrSpace(Arg);
+        if (AssumedAS != ~0U)
+          return takeAddressSpace(AssumedAS);
       }
       return takeAddressSpace(Obj.getType()->getPointerAddressSpace());
     };