[llvm] [PGO][ICP] Prevent indirect call promotion to functions with incompatible target features (PR #192142)

[Han Shen via llvm-commits]

================
@@ -0,0 +1,50 @@
+; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/norepeated-icp-2.prof -S | FileCheck %s
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at p = dso_local global ptr null, align 8
+
+; Function Attrs: uwtable mustprogress
+define dso_local void @_Z3moov() #0 !dbg !7 {
+entry:
+  ret void
+}
+
+; Function Attrs: uwtable mustprogress
+define dso_local void @_Z3hoov() #1 !dbg !11 {
+entry:
+  store ptr @_Z3moov, ptr @p, align 8
+  ret void
+}
+
+; Function Attrs: uwtable mustprogress
+define dso_local void @_Z3goov() #1 !dbg !24 {
+entry:
+  %t0 = load ptr, ptr @p, align 8
+  ; CHECK: icmp eq ptr %t0, @_Z3hoov
+  ; CHECK-NOT: icmp eq ptr %t0, @_Z3moov
+  call void %t0(), !dbg !26, !prof !30
+  ret void
+}
+
+attributes #0 = { uwtable mustprogress "use-sample-profile" "target-features"="+avx512f" }
+attributes #1 = { uwtable mustprogress "use-sample-profile" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2, splitDebugInlining: false, debugInfoForProfiling: true, nameTableKind: None)
+!1 = !DIFile(filename: "1.cc", directory: "")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang"}
+!7 = distinct !DISubprogram(name: "moo", linkageName: "_Z3moov", scope: !1, file: !1, line: 1, type: !8, scopeLine: 1, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!8 = !DISubroutineType(types: !2)
+!11 = distinct !DISubprogram(name: "hoo", linkageName: "_Z3hoov", scope: !1, file: !1, line: 9, type: !8, scopeLine: 9, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!24 = distinct !DISubprogram(name: "goo", linkageName: "_Z3goov", scope: !1, file: !1, line: 15, type: !8, scopeLine: 15, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!26 = !DILocation(line: 16, column: 3, scope: !24)
+!30 = !{!"VP", i32 0, i64 0, i64 1850239051784516332, i64 -1}
----------------
shenhanc78 wrote:

Excellent catch! Under Sample PGO (-passes=sample-profile), the SampleProfileLoader retrieves candidate targets directly from the sample profile file (Inputs/norepeated-icp-2.prof) at line offset 1, where both _Z3hoov and _Z3moov are listed as inline candidates:

```
1: _Z3hoov:5860
   1: 5000
 1: _Z3moov:5860
   1: 5000
```

Since these are loaded directly from the profile, both are attempted for promotion. I realized that the original !prof !30 metadata on the call instruction and the !30 definition were completely redundant. I have removed them to simplify the test IR, and documented this Sample PGO behavior in the top-level comment. Without the target features compatibility check, the test indeed fails because @_Z3moov gets incorrectly promoted.

https://github.com/llvm/llvm-project/pull/192142