[HLSL] skip unused global resource when collect resources.

[python3kgae]

Summary

Only used global resource should be added to resource table for DXIL.
Assume optimization runs before collecting resources.

[python3kgae]

Rebase.

llvm/lib/Target/DirectX/DXILResource.cpp

 
 void Resources::collectUAVs(Module &M) {
   NamedMDNode *Entry = M.getNamedMetadata("hlsl.uavs");
   if (!Entry || Entry->getNumOperands() == 0)
     return;
 
   uint32_t Counter = 0;
   for (auto *UAV : Entry->operands()) {
-    UAVs.push_back(UAVResource(Counter++, FrontendResource(cast<MDNode>(UAV))));
+    auto Res = FrontendResource(cast<MDNode>(UAV));
+    if (Res.getGlobalVariable()->user_empty())
+      continue;
+    UAVs.push_back(UAVResource(Counter++, Res));
   }
 }
 
 void Resources::collect(Module &M) { collectUAVs(M); }
 
 ResourceBase::ResourceBase(uint32_t I, FrontendResource R)
     : ID(I), GV(R.getGlobalVariable()), Name(""), Space(R.getSpace()),
       LowerBound(R.getResourceIndex()), RangeSize(1) {

llvm/test/CodeGen/DirectX/UAVMetadata.ll

 @Three = local_unnamed_addr global [2 x %"class.hlsl::RWBuffer"] zeroinitializer, align 4
 @Four = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Five = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Six = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Seven = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Eight = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Nine = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 
+define void @"foo"() #0 {
+  %ld0 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Zero
+  %ld1 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @One
+  %ld2 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Two
+  %ld3 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Three
+  %ld4 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Four
+  %ld5 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Five
+  %ld6 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Six
+  %ld7 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Seven
+  %ld8 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Eight
+  %ld9 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Nine
+  ret void
+}
+attributes #0 = { noinline optnone }
 
 !hlsl.uavs = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9}
 
 !0 = !{ptr @Zero, !"RWBuffer<half>", i32 0, i32 10, i32 0, i32 0}
 !1 = !{ptr @One, !"Buffer<vector<float,4>>", i32 1, i32 10, i32 1, i32 0}
 !2 = !{ptr @Two, !"Buffer<double>", i32 2, i32 10, i32 2, i32 0}
 !3 = !{ptr @Three, !"Buffer<bool>", i32 3, i32 10, i32 3, i32 0}
 !4 = !{ptr @Four, !"ByteAddressBuffer<int16_t>", i32 4, i32 11, i32 5, i32 0}

llvm/test/CodeGen/DirectX/UnusedUAV.ll

 ; PRINT:; Resource Bindings:
 ; PRINT-NEXT:;
 ; PRINT-NEXT:; Name                                 Type  Format         Dim      ID      HLSL Bind  Count
 ; PRINT-NEXT:; ------------------------------ ---------- ------- ----------- ------- -------------- ------
 ; PRINT-NEXT:;                                       UAV     f16         buf      U0             u0     1
 ; PRINT-NEXT:;                                       UAV     f32         buf      U1             u1     1
 ; PRINT-NEXT:;                                       UAV     f64         buf      U2             u2     1
 ; PRINT-NEXT:;                                       UAV      i1         buf      U3             u3     2
-; PRINT-NEXT:;                                       UAV    byte         r/w      U4             u5     1
-; PRINT-NEXT:;                                       UAV  struct         r/w      U5             u6     1
-; PRINT-NEXT:;                                       UAV     i32         buf      U6             u7     1
-; PRINT-NEXT:;                                       UAV  struct         r/w      U7             u8     1
-; PRINT-NEXT:;                                       UAV    byte         r/w      U8             u9     1
-; PRINT-NEXT:;                                       UAV     u64         buf      U9     u10,space2     1
+; PRINT-NEXT:;                                       UAV  struct         r/w      U4             u6     1
+; PRINT-NEXT:;                                       UAV     i32         buf      U5             u7     1
+; PRINT-NEXT:;                                       UAV    byte         r/w      U6             u9     1
+; PRINT-NEXT:;                                       UAV     u64         buf      U7     u10,space2     1
 
 @Zero = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @One = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Two = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Three = local_unnamed_addr global [2 x %"class.hlsl::RWBuffer"] zeroinitializer, align 4
 @Four = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Five = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Six = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Seven = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Eight = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 @Nine = local_unnamed_addr global %"class.hlsl::RWBuffer" zeroinitializer, align 4
 
+define void @"foo"() #0 {
+  %ld0 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Zero
+  %ld1 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @One
+  %ld2 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Two
+  %ld3 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Three
+  %ld5 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Five
+  %ld6 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Six
+  %ld8 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Eight
+  %ld9 = load %"class.hlsl::RWBuffer", %"class.hlsl::RWBuffer"* @Nine
+  ret void
+}
+attributes #0 = { noinline optnone }
 
 !hlsl.uavs = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9}
 
 !0 = !{ptr @Zero, !"RWBuffer<half>", i32 0, i32 10, i32 0, i32 0}
 !1 = !{ptr @One, !"Buffer<vector<float,4>>", i32 1, i32 10, i32 1, i32 0}
 !2 = !{ptr @Two, !"Buffer<double>", i32 2, i32 10, i32 2, i32 0}
 !3 = !{ptr @Three, !"Buffer<bool>", i32 3, i32 10, i32 3, i32 0}
 !4 = !{ptr @Four, !"ByteAddressBuffer<int16_t>", i32 4, i32 11, i32 5, i32 0}
 !5 = !{ptr @Five, !"StructuredBuffer<uint16_t>", i32 5, i32 12, i32 6, i32 0}
 !6 = !{ptr @Six, !"RasterizerOrderedBuffer<int32_t>", i32 6, i32 10, i32 7, i32 0}
 !7 = !{ptr @Seven, !"RasterizerOrderedStructuredBuffer<uint32_t>", i32 7, i32 12, i32 8, i32 0}
 !8 = !{ptr @Eight, !"RasterizerOrderedByteAddressBuffer<int64_t>", i32 8, i32 11, i32 9, i32 0}
 !9 = !{ptr @Nine, !"RWBuffer<uint64_t>", i32 9, i32 10, i32 10, i32 2}
 
 ; CHECK: !dx.resources = !{[[ResList:[!][0-9]+]]}
 
 ; CHECK: [[ResList]] = !{null, [[UAVList:[!][0-9]+]], null, null}
 ; CHECK: [[UAVList]] = !{[[Zero:[!][0-9]+]], [[One:[!][0-9]+]],
-; CHECK-SAME: [[Two:[!][0-9]+]], [[Three:[!][0-9]+]], [[Four:[!][0-9]+]], 
-; CHECK-SAME: [[Five:[!][0-9]+]], [[Six:[!][0-9]+]], [[Seven:[!][0-9]+]],
+; CHECK-SAME: [[Two:[!][0-9]+]], [[Three:[!][0-9]+]],
+; CHECK-SAME: [[Five:[!][0-9]+]], [[Six:[!][0-9]+]],
 ; CHECK-SAME: [[Eight:[!][0-9]+]], [[Nine:[!][0-9]+]]}
 ; CHECK: [[Zero]] = !{i32 0, ptr @Zero, !"", i32 0, i32 0, i32 1, i32 10, i1 false, i1 false, i1 false, [[Half:[!][0-9]+]]}
 ; CHECK: [[Half]] = !{i32 0, i32 8}
 ; CHECK: [[One]] = !{i32 1, ptr @One, !"", i32 0, i32 1, i32 1, i32 10, i1 false, i1 false, i1 false, [[Float:[!][0-9]+]]}
 ; CHECK: [[Float]] = !{i32 0, i32 9}
 ; CHECK: [[Two]] = !{i32 2, ptr @Two, !"", i32 0, i32 2, i32 1, i32 10, i1 false, i1 false, i1 false, [[Double:[!][0-9]+]]}
 ; CHECK: [[Double]] = !{i32 0, i32 10}
 ; CHECK: [[Three]] = !{i32 3, ptr @Three, !"", i32 0, i32 3, i32 2, i32 10, i1 false, i1 false, i1 false, [[Bool:[!][0-9]+]]}
 ; CHECK: [[Bool]] = !{i32 0, i32 1}
-; CHECK: [[Four]] = !{i32 4, ptr @Four, !"", i32 0, i32 5, i32 1, i32 11, i1 false, i1 false, i1 false, [[I16:[!][0-9]+]]}
-; CHECK: [[I16]] = !{i32 0, i32 2}
-; CHECK: [[Five]] = !{i32 5, ptr @Five, !"", i32 0, i32 6, i32 1, i32 12, i1 false, i1 false, i1 false, [[U16:[!][0-9]+]]}
+; CHECK: [[Five]] = !{i32 4, ptr @Five, !"", i32 0, i32 6, i32 1, i32 12, i1 false, i1 false, i1 false, [[U16:[!][0-9]+]]}
 ; CHECK: [[U16]] = !{i32 0, i32 3}
-; CHECK: [[Six]] = !{i32 6, ptr @Six, !"", i32 0, i32 7, i32 1, i32 10, i1 false, i1 false, i1 true, [[I32:[!][0-9]+]]}
+; CHECK: [[Six]] = !{i32 5, ptr @Six, !"", i32 0, i32 7, i32 1, i32 10, i1 false, i1 false, i1 true, [[I32:[!][0-9]+]]}
 ; CHECK: [[I32]] = !{i32 0, i32 4}
-; CHECK: [[Seven]] = !{i32 7, ptr @Seven, !"", i32 0, i32 8, i32 1, i32 12, i1 false, i1 false, i1 true, [[U32:[!][0-9]+]]}
-; CHECK: [[U32]] = !{i32 0, i32 5}
-; CHECK: [[Eight]] = !{i32 8, ptr @Eight, !"", i32 0, i32 9, i32 1, i32 11, i1 false, i1 false, i1 true, [[I64:[!][0-9]+]]}
+; CHECK: [[Eight]] = !{i32 6, ptr @Eight, !"", i32 0, i32 9, i32 1, i32 11, i1 false, i1 false, i1 true, [[I64:[!][0-9]+]]}
 ; CHECK: [[I64]] = !{i32 0, i32 6}
-; CHECK: [[Nine]] = !{i32 9, ptr @Nine, !"", i32 2, i32 10, i32 1, i32 10, i1 false, i1 false, i1 false, [[U64:[!][0-9]+]]}
+; CHECK: [[Nine]] = !{i32 7, ptr @Nine, !"", i32 2, i32 10, i32 1, i32 10, i1 false, i1 false, i1 false, [[U64:[!][0-9]+]]}
 ; CHECK: [[U64]] = !{i32 0, i32 7}