diff --git a/llvm/include/llvm/MC/MCAsmInfo.h b/llvm/include/llvm/MC/MCAsmInfo.h
--- a/llvm/include/llvm/MC/MCAsmInfo.h
+++ b/llvm/include/llvm/MC/MCAsmInfo.h
@@ -209,6 +209,9 @@
   const char *Data32bitsDirective;
   const char *Data64bitsDirective;
 
+  /// True if data directives support signed values
+  bool SupportsSignedData = true;
+
   /// If non-null, a directive that is used to emit a word which should be
   /// relocated as a 64-bit GP-relative offset, e.g. .gpdword on Mips.  Defaults
   /// to nullptr.
@@ -440,6 +443,7 @@
   const char *getData16bitsDirective() const { return Data16bitsDirective; }
   const char *getData32bitsDirective() const { return Data32bitsDirective; }
   const char *getData64bitsDirective() const { return Data64bitsDirective; }
+  bool supportsSignedData() const { return SupportsSignedData; }
   const char *getGPRel64Directive() const { return GPRel64Directive; }
   const char *getGPRel32Directive() const { return GPRel32Directive; }
   const char *getDTPRel64Directive() const { return DTPRel64Directive; }
diff --git a/llvm/lib/MC/MCExpr.cpp b/llvm/lib/MC/MCExpr.cpp
--- a/llvm/lib/MC/MCExpr.cpp
+++ b/llvm/lib/MC/MCExpr.cpp
@@ -65,6 +65,8 @@
         OS << format("0x%016" PRIx64, Value);
         break;
       }
+    else if (MAI && !MAI->supportsSignedData())
+      OS << static_cast<uint64_t>(Value);
     else
       OS << Value;
     return;
diff --git a/llvm/lib/Target/NVPTX/MCTargetDesc/NVPTXMCAsmInfo.cpp b/llvm/lib/Target/NVPTX/MCTargetDesc/NVPTXMCAsmInfo.cpp
--- a/llvm/lib/Target/NVPTX/MCTargetDesc/NVPTXMCAsmInfo.cpp
+++ b/llvm/lib/Target/NVPTX/MCTargetDesc/NVPTXMCAsmInfo.cpp
@@ -47,6 +47,7 @@
   AscizDirective = nullptr; // not supported
   SupportsQuotedNames = false;
   SupportsExtendedDwarfLocDirective = false;
+  SupportsSignedData = false;
 
   // @TODO: Can we just disable this?
   WeakDirective = "\t// .weak\t";
diff --git a/llvm/test/CodeGen/NVPTX/data-direcitve-negative-values.ll b/llvm/test/CodeGen/NVPTX/data-direcitve-negative-values.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/NVPTX/data-direcitve-negative-values.ll
@@ -0,0 +1,71 @@
+; PTX only allows unsigned values in .b64/32/8 directives.  However,
+; MCAsmPrinter only deals with int64 values and if the value happens to be
+; negative, we ended up with invalid PTX. Fortunately, data directives are
+; almost never produced and when they are, they are normally used with small
+; unsigned values representable by int64. One exception is DWARF which emits a
+; lot of data and some of the values may be negative. The IR below has been
+; produced by the following CUDA code compiled with DWARF debug info enabled.
+;
+;struct {
+;  char : 3;
+;  char a : 6;
+;} __attribute__((__packed__)) b;
+;__attribute__((global)) void c() { auto d = b; }
+;
+; RUN: llc -O0 < %s -march=nvptx64 -mcpu=sm_60 | FileCheck %s
+;
+; Make sure there are no negative values
+; CHECK-NOT: .b64 -
+;
+target datalayout = "e-i64:64-i128:128-v16:16-v32:32-n16:32:64"
+target triple = "nvptx64-nvidia-cuda"
+
+%struct.anon = type { i16 }
+
+@b = external dso_local addrspace(1) global %struct.anon, align 1
+
+; Function Attrs: convergent noinline norecurse nounwind optnone
+define dso_local void @_Z1cv() #0 !dbg !9 {
+entry:
+  %d = alloca %struct.anon, align 1
+  call void @llvm.dbg.declare(metadata %struct.anon* %d, metadata !12, metadata !DIExpression()), !dbg !17
+  %0 = bitcast %struct.anon* %d to i8*, !dbg !18
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 1 %0, i8* align 1 addrspacecast (i8 addrspace(1)* bitcast (%struct.anon addrspace(1)* @b to i8 addrspace(1)*) to i8*), i64 2, i1 false), !dbg !18
+  ret void, !dbg !19
+}
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg) #2
+
+attributes #0 = { convergent noinline norecurse nounwind optnone "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" "target-cpu"="sm_60" "target-features"="+ptx32,+sm_60" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone speculatable willreturn }
+attributes #2 = { argmemonly nounwind willreturn }
+
+!llvm.dbg.cu = !{!0}
+!nvvm.annotations = !{!3}
+!llvm.module.flags = !{!4, !5, !6, !7}
+!llvm.ident = !{!8}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_11, file: !1, producer: "clang version 11.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "b64.cu", directory: "/usr/local/google/home/tra/work/llvm/build/debug")
+!2 = !{}
+!3 = !{void ()* @_Z1cv, !"kernel", i32 1}
+!4 = !{i32 7, !"Dwarf Version", i32 2}
+!5 = !{i32 2, !"Debug Info Version", i32 3}
+!6 = !{i32 1, !"wchar_size", i32 4}
+!7 = !{i32 4, !"nvvm-reflect-ftz", i32 0}
+!8 = !{!"clang version 11.0.0 "}
+!9 = distinct !DISubprogram(name: "c", linkageName: "_Z1cv", scope: !1, file: !1, line: 5, type: !10, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!10 = !DISubroutineType(types: !11)
+!11 = !{null}
+!12 = !DILocalVariable(name: "d", scope: !9, file: !1, line: 5, type: !13)
+!13 = distinct !DICompositeType(tag: DW_TAG_structure_type, file: !1, line: 1, size: 16, flags: DIFlagTypePassByValue, elements: !14)
+!14 = !{!15}
+!15 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !13, file: !1, line: 3, baseType: !16, size: 6, offset: 3, flags: DIFlagBitField, extraData: i64 0)
+!16 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!17 = !DILocation(line: 5, column: 41, scope: !9)
+!18 = !DILocation(line: 5, column: 45, scope: !9)
+!19 = !DILocation(line: 5, column: 48, scope: !9)