[AMDGPU] Fix assertion due to assuming pointer in default addr space is 32 bit

[yaxunl]

Summary

The backend assumes pointer in default addr space is 32 bit, which is not
true for the new addr space mapping and causes assertion for unresolved
functions.

This patch fixes that.

[arsenm]

LGTM

lib/Target/AMDGPU/SIISelLowering.cpp

2136

You should be able to just remove this whole block when the triple setting is removed

[yaxunl]

lib/Target/AMDGPU/SIISelLowering.cpp

2136

Yes I will do that.

lib/Target/AMDGPU/SIISelLowering.cpp

     // to change that but can still do a tail call:
     if (!TailCallOpt && IsTailCall)
       IsSibCall = true;
 
     if (IsTailCall)
       ++NumTailCalls;
   }
 
   if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Callee)) {
-    // FIXME: Remove this hack for function pointer types.
-    const GlobalValue *GV = GA->getGlobal();
-    assert(Callee.getValueType() == MVT::i32);
-    Callee = DAG.getGlobalAddress(GV, DL, MVT::i64, GA->getOffset(),
-                                  false, GA->getTargetFlags());
+    // FIXME: Remove this hack for function pointer types after removing
+    // support of old address space mapping. In the new address space
+    // mapping the pointer in default address space is 64 bit, therefore
+    // does not need this hack.
+    if (Callee.getValueType() == MVT::i32) {
+      const GlobalValue *GV = GA->getGlobal();
+      Callee = DAG.getGlobalAddress(GV, DL, MVT::i64, GA->getOffset(), false,
+                                    GA->getTargetFlags());
+    }
   }
+  assert(Callee.getValueType() == MVT::i64);
 
   const SIMachineFunctionInfo *Info = MF.getInfo<SIMachineFunctionInfo>();
 
   // Analyze operands of the call, assigning locations to each operand.
   SmallVector<CCValAssign, 16> ArgLocs;
   CCState CCInfo(CallConv, IsVarArg, MF, ArgLocs, *DAG.getContext());
   CCAssignFn *AssignFn = CCAssignFnForCall(CallConv, IsVarArg);
   CCInfo.AnalyzeCallOperands(Outs, AssignFn);

test/CodeGen/AMDGPU/unsupported-calls.ll

-; RUN: not llc -march=amdgcn -tailcallopt < %s 2>&1 | FileCheck -check-prefix=GCN %s
-; RUN: not llc -march=r600 -mcpu=cypress -tailcallopt < %s 2>&1 | FileCheck -check-prefix=R600 %s
+; RUN: not llc -march=amdgcn -mtriple=amdgcn---amdgiz -tailcallopt < %s 2>&1 | FileCheck -check-prefix=GCN %s
+; RUN: not llc -march=r600 -mtriple=r600---amdgiz -mcpu=cypress -tailcallopt < %s 2>&1 | FileCheck -check-prefix=R600 %s
 
 declare i32 @external_function(i32) nounwind
 
 ; GCN-NOT: error
 ; R600: in function test_call_external{{.*}}: unsupported call to function external_function
 define amdgpu_kernel void @test_call_external(i32 addrspace(1)* %out, i32 addrspace(1)* %in) {
   %b_ptr = getelementptr i32, i32 addrspace(1)* %in, i32 1
   %a = load i32, i32 addrspace(1)* %in