Revert "Revert r347596 "Support for inserting profile-directed cache prefetches""

Summary:
This reverts commit d8517b96dfbd42e6a8db33c50d1fa1e58e63fbb9.

Fix: correct  the use of DenseMap.

Reviewers: davidxl, hans, wmi

Reviewed By: wmi

Subscribers: mgorny, eraman, llvm-commits

Differential Revision: https://reviews.llvm.org/D55088

llvm-svn: 347938
diff --git a/llvm/test/CodeGen/X86/insert-prefetch-invalid-instr.ll b/llvm/test/CodeGen/X86/insert-prefetch-invalid-instr.ll
new file mode 100644
index 0000000..004fb56
--- /dev/null
+++ b/llvm/test/CodeGen/X86/insert-prefetch-invalid-instr.ll
@@ -0,0 +1,46 @@
+; RUN: llc < %s -prefetch-hints-file=%S/insert-prefetch-invalid-instr.afdo | FileCheck %s
+; ModuleID = 'prefetch.cc'
+source_filename = "prefetch.cc"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: norecurse nounwind uwtable
+define dso_local i32 @main() local_unnamed_addr #0 !dbg !7 {
+entry:
+  tail call void @llvm.prefetch(i8* inttoptr (i64 291 to i8*), i32 0, i32 0, i32 1), !dbg !9
+  tail call void @llvm.x86.avx512.gatherpf.dpd.512(i8 97, <8 x i32> undef, i8* null, i32 1, i32 2), !dbg !10
+  ret i32 291, !dbg !11
+}
+
+; Function Attrs: inaccessiblemem_or_argmemonly nounwind
+declare void @llvm.prefetch(i8* nocapture readonly, i32, i32, i32) #1
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.x86.avx512.gatherpf.dpd.512(i8, <8 x i32>, i8*, i32, i32) #2
+
+attributes #0 = {"target-cpu"="x86-64" "target-features"="+avx512pf,+sse4.2,+ssse3"}
+attributes #1 = { inaccessiblemem_or_argmemonly nounwind }
+attributes #2 = { argmemonly nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2, debugInfoForProfiling: true)
+!1 = !DIFile(filename: "prefetch.cc", directory: "/tmp")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 7.0.0 (trunk 327078) (llvm/trunk 327086)"}
+!7 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 8, type: !8, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: true, unit: !0)
+!8 = !DISubroutineType(types: !2)
+!9 = !DILocation(line: 12, column: 3, scope: !7)
+!10 = !DILocation(line: 14, column: 3, scope: !7)
+!11 = !DILocation(line: 15, column: 3, scope: !7)
+
+;CHECK-LABEL: main:
+;CHECK:       # %bb.0:
+;CHECK:       prefetchnta 291
+;CHECK-NOT:   prefetchnta 42(%rax,%ymm0)
+;CHECK:       vgatherpf1dpd (%rax,%ymm0) {%k1}