[llvm] [SEH][CodeGen] Add test to track CFG optimization bug for SEH (PR #77441)

[via llvm-commits]

https://github.com/HaohaiWen created https://github.com/llvm/llvm-project/pull/77441

LiveDebugValues requires CFG only has one entry. BranchFolding and
MachineBlockPlacement may remove all predecessors of landing pad which
leaves it to be another entry.

>From d043e85853c94e07c9e6d089c7eab42895f8eb4c Mon Sep 17 00:00:00 2001
From: Haohai Wen <haohai.wen at intel.com>
Date: Tue, 9 Jan 2024 18:35:33 +0800
Subject: [PATCH] [SEH][CodeGen] Add test to track CFG optimization bug for SEH

LiveDebugValues requires CFG only has one entry. BranchFolding and
MachineBlockPlacement may remove all predecessors of landing pad which
leaves it to be another entry.
---
 .../X86/windows-seh-EHa-PreserveCFG.ll        | 81 +++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 llvm/test/CodeGen/X86/windows-seh-EHa-PreserveCFG.ll

diff --git a/llvm/test/CodeGen/X86/windows-seh-EHa-PreserveCFG.ll b/llvm/test/CodeGen/X86/windows-seh-EHa-PreserveCFG.ll
new file mode 100644
index 00000000000000..bd6743f7c414b4
--- /dev/null
+++ b/llvm/test/CodeGen/X86/windows-seh-EHa-PreserveCFG.ll
@@ -0,0 +1,81 @@
+; XFAIL: *
+; RUN: llc -mtriple=x86_64-pc-windows-msvc %s
+define dso_local void @main(ptr %addr, ptr %src, ptr %dst) personality ptr @__CxxFrameHandler3 !dbg !11 {
+entry:
+  %tmp0 = load float, ptr %src
+  %src1 = getelementptr inbounds float, ptr %src, i64 1
+  %tmp1 = load float, ptr %src1
+  %src2 = getelementptr inbounds float, ptr %src, i64 2
+  %tmp2 = load float, ptr %src2
+  %src3 = getelementptr inbounds float, ptr %src, i64 3
+  %tmp3 = load float, ptr %src3
+  %src4 = getelementptr inbounds float, ptr %src, i64 4
+  %tmp4 = load float, ptr %src4
+  %src5 = getelementptr inbounds float, ptr %src, i64 5
+  %tmp5 = load float, ptr %src5
+  %src6 = getelementptr inbounds float, ptr %src, i64 6
+  %tmp6 = load float, ptr %src6
+  invoke void @foo(ptr %addr)
+          to label %scope_begin unwind label %ehcleanup1, !dbg !13
+
+scope_begin:
+  invoke void @llvm.seh.scope.begin()
+          to label %scope_end unwind label %ehcleanup, !dbg !13
+
+scope_end:
+  invoke void @llvm.seh.scope.end()
+          to label %finish unwind label %ehcleanup, !dbg !13
+
+ehcleanup:
+  %0 = cleanuppad within none [], !dbg !13
+  call void @llvm.dbg.value(metadata ptr %addr, metadata !12, metadata !DIExpression()), !dbg !13
+  call void @foo(ptr %addr) [ "funclet"(token %0) ], !dbg !13
+  cleanupret from %0 unwind label %ehcleanup1, !dbg !13
+
+ehcleanup1:
+  %1 = cleanuppad within none [], !dbg !13
+  call void @foo(ptr %addr) [ "funclet"(token %1) ], !dbg !13
+  cleanupret from %1 unwind to caller, !dbg !13
+
+finish:
+  store float %tmp0, ptr %dst
+  %dst1 = getelementptr inbounds float, ptr %dst, i64 1
+  store float %tmp1, ptr %dst1
+  %dst2 = getelementptr inbounds float, ptr %dst, i64 2
+  store float %tmp2, ptr %dst2
+  %dst3 = getelementptr inbounds float, ptr %dst, i64 3
+  store float %tmp3, ptr %dst3
+  %dst4 = getelementptr inbounds float, ptr %dst, i64 4
+  store float %tmp4, ptr %dst4
+  %dst5 = getelementptr inbounds float, ptr %dst, i64 5
+  store float %tmp5, ptr %dst5
+  %dst6 = getelementptr inbounds float, ptr %dst, i64 6
+  store float %tmp6, ptr %dst6
+  ret void
+}
+
+declare dso_local void @llvm.seh.scope.begin()
+declare dso_local void @llvm.seh.scope.end()
+declare dso_local i32 @__CxxFrameHandler3(...)
+declare dso_local void @foo(ptr %addr)
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+!llvm.module.flags = !{!0, !1, !2, !3}
+!llvm.dbg.cu = !{!14}
+
+!0 = !{i32 2, !"eh-asynch", i32 1}
+!1 = !{i32 2, !"CodeView", i32 1}
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = !{i32 7, !"uwtable", i32 2}
+
+!4 = !DIBasicType(name: "float", size: 32, encoding: DW_ATE_float)
+!5 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !4, size: 64)
+!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!7 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !6, size: 64)
+!8 = !DISubroutineType(types: !9)
+!9 = !{null, !7, !5, !5}
+!10 = !DIFile(filename: "c:/main.cpp", directory: "")
+!11 = distinct !DISubprogram(name: "main", scope: !10, file: !10, line: 5, type: !8, scopeLine: 11, unit: !14)
+!12 = !DILocalVariable(name: "addr", scope: !11, file: !10, line: 5, type: !7)
+!13 = !DILocation(line: 7, scope: !11)
+!14 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !10, isOptimized: true, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)