Do not inline recursive direct calls in sample loader pass.

[danielcdh]

Summary

r305009 disables recursive inlining for indirect calls in sample loader pass. The same logic applies to direct recursive calls.

lib/Transforms/IPO/SampleProfile.cpp

for (auto &BB : F) {
       }
       if (Hot) {
         CIS.insert(CIS.begin(), Candidates.begin(), Candidates.end());
       }
     }
     for (auto I : CIS) {
       InlineFunctionInfo IFI(nullptr, ACT ? &GetAssumptionCache : nullptr);
       Function *CalledFunction = CallSite(I).getCalledFunction();
+      // Do not inline recursive calls.
+      if (CalledFunction == &F)
+        continue;
       Instruction *DI = I;
       if (!CalledFunction && !PromotedInsns.count(I) &&
           CallSite(I).isIndirectCall())
         for (const auto *FS : findIndirectCallFunctionSamples(*I)) {
           auto CalleeFunctionName = FS->getName();
           // If it is a recursive call, we do not inline it as it could bloat
           // the code exponentially. There is way to better handle this, e.g.
           // clone the caller first, and inline the cloned caller if it is

test/Transforms/SampleProfile/Inputs/einline.prof

 _Z3foov:200:100
  1: _Z3barv:0
  3: _Z3barv:100
+recursive:200:100
+ 1: recursive:100
+ 2: recursive:100

test/Transforms/SampleProfile/early-inline.ll

; <label>:5:
   ret void
 }
 
 ; Function Attrs: nounwind uwtable
 define internal void @_ZL3barv() !dbg !12 {
   ret void
 }
 
+; CHECK-LABEL: @recursive
+define void @recursive() !dbg !13 {
+; Recursive calls should not be early-inlined.
+; CHECK-NOT: call void @recursive
+; CHECK: call void @recursive
+; CHECK: call void @recursive
+; CHECK-NOT: call void @recursive
+; CHECK: ret
+  call void @recursive(), !dbg !14
+  call void @recursive(), !dbg !15
+  ret void
+}
+
 declare i32 @__gxx_personality_v0(...)
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!3, !4}
 
 !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1)
 !1 = !DIFile(filename: "a", directory: "b/")
 !3 = !{i32 2, !"Dwarf Version", i32 4}
 !4 = !{i32 2, !"Debug Info Version", i32 3}
 !6 = distinct !DISubprogram(linkageName: "_Z3foov", scope: !1, file: !1, line: 5, scopeLine: 5, unit: !0)
 !9 = !DILocation(line: 6, column: 3, scope: !6)
 !10 = !DILocation(line: 8, column: 5, scope: !11)
 !11 = distinct !DILexicalBlock(scope: !6, file: !1, line: 7, column: 7)
 !12 = distinct !DISubprogram(linkageName: "_ZL3barv", scope: !1, file: !1, line: 20, scopeLine: 20, unit: !0)
+!13 = distinct !DISubprogram(linkageName: "recursive", scope: !1, file: !1, line: 20, scopeLine: 20, unit: !0)
+!14 = !DILocation(line: 21, column: 3, scope: !13)
+!15 = !DILocation(line: 22, column: 3, scope: !13)