Fixed a crash due to an incorrect call to dropAllReferences (#5102)

Fixed a crash when there's addrspacecast going into a getelementptr, which goes into a dbg.decare. The HLSL SROA pass was incorrectly calling dropAllReferences on the addrspacecast ConstExpr, which invalidates the getelementptr ConstExpr (sets the operand to nullptr).

lib/Transforms/Scalar/ScalarReplAggregatesHLSL.cpp

@@ -1674,9 +1674,6 @@ void RemoveUnusedInternalGlobalVariable(Module &M) {
         Value *User = *(UserIt++);
         if (Instruction *I = dyn_cast<Instruction>(User)) {
           I->eraseFromParent();
-        } else {
-          ConstantExpr *CE = cast<ConstantExpr>(User);
-          CE->dropAllReferences();
         }
       }
       GV->eraseFromParent();

tools/clang/test/HLSLFileCheck/passes/hl/sroa_hlsl/addrspacecast_dbg_crash.ll

@@ -0,0 +1,177 @@
+; RUN: %opt %s -hlsl-passes-resume -scalarrepl-param-hlsl -S | FileCheck %s
+
+; Check that the global struct is completely gone
+; CHECK-NOT: @"\01?foo@@3UStruct@@A
+
+; CHECK: @main
+
+; Regression test for a crash when there's addrspacecast going into a
+; getelementptr, which goes into a dbg.decare. The pass was
+; incorrectly calling dropAllReferences on the addrspacecast
+; ConstExpr, which invalidates the getelementptr ConstExpr (sets the
+; operand to nullptr).
+
+; The test was made with the following original HLSL, and then manually
+; reduced to just the lines that cause problems:
+
+;; void GlobalSet(inout float x, float val) {
+;;   x = 10;
+;; }
+;; struct Struct {
+;;   int x;
+;;   float y;
+;;   void Set(float val) {
+;;     GlobalSet(x, val);
+;;     GlobalSet(y, val);
+;;   }
+;; };
+;;
+;; groupshared Struct foo;
+;;
+;; float main() : SV_Target {
+;;   foo.Set(10);
+;;   return 0;
+;; }
+;;
+
+;
+; Buffer Definitions:
+;
+; cbuffer $Globals
+; {
+;
+;   [0 x i8] (type annotation not present)
+;
+; }
+;
+;
+; Resource Bindings:
+;
+; Name                                 Type  Format         Dim      ID      HLSL Bind  Count
+; ------------------------------ ---------- ------- ----------- ------- -------------- ------
+; $Globals                          cbuffer      NA          NA     CB0   cb4294967295     1
+;
+target datalayout = "e-m:e-p:32:32-i1:32-i8:32-i16:32-i32:32-i64:64-f16:32-f32:32-f64:64-n8:16:32:64"
+target triple = "dxil-ms-dx"
+
+%struct.Struct = type { i32, float }
+%ConstantBuffer = type opaque
+
+@"\01?foo@@3UStruct@@A" = external addrspace(3) global %struct.Struct, align 4
+@"$Globals" = external constant %ConstantBuffer
+
+; Function Attrs: nounwind
+define float @main() #0 {
+entry:
+  call void @llvm.dbg.declare(metadata float* getelementptr (%struct.Struct, %struct.Struct* addrspacecast (%struct.Struct addrspace(3)* @"\01?foo@@3UStruct@@A" to %struct.Struct*), i32 0, i32 1), metadata !74, metadata !57), !dbg !75 ; var:"x" !DIExpression() func:"GlobalSet"
+  store float 1.000000e+01, float addrspace(3)* getelementptr inbounds (%struct.Struct, %struct.Struct addrspace(3)* @"\01?foo@@3UStruct@@A", i32 0, i32 1), align 4, !dbg !77, !tbaa !51, !alias.scope !71 ; line:3 col:5
+  ret float 0.000000e+00, !dbg !84 ; line:18 col:3
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+attributes #0 = { nounwind }
+attributes #1 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!25, !26}
+!pauseresume = !{!27}
+!llvm.ident = !{!28}
+!dx.source.contents = !{!29}
+!dx.source.defines = !{!2}
+!dx.source.mainFileName = !{!30}
+!dx.source.args = !{!31}
+!dx.version = !{!32}
+!dx.valver = !{!33}
+!dx.shaderModel = !{!34}
+!dx.typeAnnotations = !{!35, !39}
+!dx.entryPoints = !{!43}
+!dx.fnprops = !{!47}
+!dx.options = !{!48, !49}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "dxc(private) 1.7.0.3788 (no_structurize_return_for_lifetime, deb91beeb)", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3, globals: !23)
+!1 = !DIFile(filename: "f:\5C\5Caddrspacecast_crash.hlsl", directory: "")
+!2 = !{}
+!3 = !{!4, !8, !18}
+!4 = !DISubprogram(name: "main", scope: !1, file: !1, line: 16, type: !5, isLocal: false, isDefinition: true, scopeLine: 16, flags: DIFlagPrototyped, isOptimized: false, function: float ()* @main)
+!5 = !DISubroutineType(types: !6)
+!6 = !{!7}
+!7 = !DIBasicType(name: "float", size: 32, align: 32, encoding: DW_ATE_float)
+!8 = !DISubprogram(name: "Set", linkageName: "\01?Set@Struct@@QAAXM@Z", scope: !9, file: !1, line: 8, type: !15, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, declaration: !14)
+!9 = !DICompositeType(tag: DW_TAG_structure_type, name: "Struct", file: !1, line: 5, size: 64, align: 32, elements: !10)
+!10 = !{!11, !13, !14}
+!11 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !9, file: !1, line: 6, baseType: !12, size: 32, align: 32)
+!12 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!13 = !DIDerivedType(tag: DW_TAG_member, name: "y", scope: !9, file: !1, line: 7, baseType: !7, size: 32, align: 32, offset: 32)
+!14 = !DISubprogram(name: "Set", linkageName: "\01?Set@Struct@@QAAXM@Z", scope: !9, file: !1, line: 8, type: !15, isLocal: false, isDefinition: false, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false)
+!15 = !DISubroutineType(types: !16)
+!16 = !{null, !17, !7}
+!17 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 32, align: 32, flags: DIFlagArtificial | DIFlagObjectPointer)
+!18 = !DISubprogram(name: "GlobalSet", linkageName: "\01?GlobalSet@@YAXAIAMM@Z", scope: !1, file: !1, line: 2, type: !19, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false)
+!19 = !DISubroutineType(types: !20)
+!20 = !{null, !21, !7}
+!21 = !DIDerivedType(tag: DW_TAG_restrict_type, baseType: !22)
+!22 = !DIDerivedType(tag: DW_TAG_reference_type, baseType: !7)
+!23 = !{!24}
+!24 = !DIGlobalVariable(name: "foo", linkageName: "\01?foo@@3UStruct@@A", scope: !0, file: !1, line: 14, type: !9, isLocal: false, isDefinition: true, variable: %struct.Struct addrspace(3)* @"\01?foo@@3UStruct@@A")
+!25 = !{i32 2, !"Dwarf Version", i32 4}
+!26 = !{i32 2, !"Debug Info Version", i32 3}
+!27 = !{!"hlsl-hlemit", !"hlsl-hlensure"}
+!28 = !{!"dxc(private) 1.7.0.3788 (no_structurize_return_for_lifetime, deb91beeb)"}
+!29 = !{!"f:\5Cdxc\5Ctools\5Cclang\5Ctest\5CHLSLFileCheck\5Cpasses\5Chl\5Csroa_hlsl\5Caddrspacecast_crash.hlsl", !"\0D\0Avoid GlobalSet(inout float x, float val) {\0D\0A  x = 10;\0D\0A}\0D\0Astruct Struct {\0D\0A  int x;\0D\0A  float y;\0D\0A  void Set(float val) {\0D\0A    GlobalSet(x, val);\0D\0A    GlobalSet(y, val);\0D\0A  }\0D\0A};\0D\0A\0D\0Agroupshared Struct foo;\0D\0A\0D\0Afloat main() : SV_Target {\0D\0A  foo.Set(10);\0D\0A  return 0;\0D\0A}"}
+!30 = !{!"f:\5Cdxc\5Ctools\5Cclang\5Ctest\5CHLSLFileCheck\5Cpasses\5Chl\5Csroa_hlsl\5Caddrspacecast_crash.hlsl"}
+!31 = !{!"-E", !"main", !"-T", !"ps_6_0", !"-fcgl", !"/Zi", !"-Qembed_debug"}
+!32 = !{i32 1, i32 0}
+!33 = !{i32 1, i32 5}
+!34 = !{!"ps", i32 6, i32 0}
+!35 = !{i32 0, %struct.Struct undef, !36}
+!36 = !{i32 8, !37, !38}
+!37 = !{i32 6, !"x", i32 3, i32 0, i32 7, i32 4}
+!38 = !{i32 6, !"y", i32 3, i32 4, i32 7, i32 9}
+!39 = !{i32 1, float ()* @main, !40}
+!40 = !{!41}
+!41 = !{i32 1, !42, !2}
+!42 = !{i32 4, !"SV_Target", i32 7, i32 9}
+!43 = !{float ()* @main, !"main", null, !44, null}
+!44 = !{null, null, !45, null}
+!45 = !{!46}
+!46 = !{i32 0, %ConstantBuffer* @"$Globals", !"$Globals", i32 0, i32 -1, i32 1, i32 0, null}
+!47 = !{float ()* @main, i32 0, i1 false}
+!48 = !{i32 144}
+!49 = !{i32 -1}
+!50 = !DILocation(line: 17, column: 3, scope: !4)
+!51 = !{!52, !52, i64 0}
+!52 = !{!"float", !53, i64 0}
+!53 = !{!"omnipotent char", !54, i64 0}
+!54 = !{!"Simple C/C++ TBAA"}
+!55 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "this", arg: 1, scope: !8, type: !56, flags: DIFlagArtificial | DIFlagObjectPointer)
+!56 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 32, align: 32)
+!57 = !DIExpression()
+!58 = !DILocation(line: 0, scope: !8, inlinedAt: !59)
+!59 = distinct !DILocation(line: 17, column: 3, scope: !4)
+!60 = !DILocation(line: 9, column: 5, scope: !8, inlinedAt: !59)
+!61 = !{!62, !62, i64 0}
+!62 = !{!"int", !53, i64 0}
+!63 = !DILocation(line: 9, column: 18, scope: !8, inlinedAt: !59)
+!64 = !{!65}
+!65 = distinct !{!65, !66, !"\01?GlobalSet@@YAXAIAMM@Z: %x"}
+!66 = distinct !{!66, !"\01?GlobalSet@@YAXAIAMM@Z"}
+!67 = !DILocation(line: 3, column: 5, scope: !18, inlinedAt: !68)
+!68 = distinct !DILocation(line: 9, column: 5, scope: !8, inlinedAt: !59)
+!69 = !DILocation(line: 10, column: 18, scope: !8, inlinedAt: !59)
+!70 = !DILocation(line: 10, column: 5, scope: !8, inlinedAt: !59)
+!71 = !{!72}
+!72 = distinct !{!72, !73, !"\01?GlobalSet@@YAXAIAMM@Z: %x"}
+!73 = distinct !{!73, !"\01?GlobalSet@@YAXAIAMM@Z"}
+!74 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "x", arg: 1, scope: !18, file: !1, line: 2, type: !7)
+!75 = !DILocation(line: 2, column: 28, scope: !18, inlinedAt: !76)
+!76 = distinct !DILocation(line: 10, column: 5, scope: !8, inlinedAt: !59)
+!77 = !DILocation(line: 3, column: 5, scope: !18, inlinedAt: !76)
+!78 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "val", arg: 2, scope: !18, file: !1, line: 2, type: !7)
+!79 = !DILocation(line: 2, column: 37, scope: !18, inlinedAt: !76)
+!80 = !DILocation(line: 2, column: 37, scope: !18, inlinedAt: !68)
+!81 = !DILocation(line: 2, column: 28, scope: !18, inlinedAt: !68)
+!82 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "val", arg: 2, scope: !8, file: !1, line: 8, type: !7)
+!83 = !DILocation(line: 8, column: 18, scope: !8, inlinedAt: !59)
+!84 = !DILocation(line: 18, column: 3, scope: !4)