[llvm] [BranchFolding][SEH] Add test to track SEH CFG optimization (PR #77598)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-x86

Author: None (HaohaiWen)

<details>
<summary>Changes</summary>

This test tracks BranchFolding pass which removes fall through jump and
leaves landing-pad to be machine basic block of no predecessors. It
would raise bug as introduced in #<!-- -->77441.

---
Full diff: https://github.com/llvm/llvm-project/pull/77598.diff


1 Files Affected:

- (added) llvm/test/CodeGen/X86/branchfolding-landingpad-cfg.mir (+49) 


``````````diff
diff --git a/llvm/test/CodeGen/X86/branchfolding-landingpad-cfg.mir b/llvm/test/CodeGen/X86/branchfolding-landingpad-cfg.mir
new file mode 100644
index 00000000000000..a494701c2a3997
--- /dev/null
+++ b/llvm/test/CodeGen/X86/branchfolding-landingpad-cfg.mir
@@ -0,0 +1,49 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 4
+# RUN: llc -mtriple=x86_64-pc-windows-msvc -run-pass=branch-folder -o - %s | FileCheck %s
+---
+name:            main
+body:             |
+  ; CHECK-LABEL: name: main
+  ; CHECK: bb.0:
+  ; CHECK-NEXT:   successors: %bb.1(0x7ffff800), %bb.3(0x00000800)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.1:
+  ; CHECK-NEXT:   RET 0
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.2 (machine-block-address-taken, landing-pad, ehfunclet-entry):
+  ; CHECK-NEXT:   successors: %bb.3(0x80000000)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   CLEANUPRET
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.3 (landing-pad, ehfunclet-entry):
+  ; CHECK-NEXT:   CLEANUPRET
+  bb.0:
+    successors: %bb.1(0x7ffff800), %bb.5(0x00000800)
+    JMP_1 %bb.1
+
+  bb.1:
+    successors: %bb.2(0x7ffff800), %bb.4(0x00000800)
+
+    JMP_1 %bb.2
+
+  bb.2:
+    successors: %bb.3(0x7ffff800), %bb.4(0x00000800)
+
+    JMP_1 %bb.3
+
+  bb.3:
+    successors: %bb.6(0x7ffff800)
+
+    JMP_1 %bb.6
+
+  bb.4 (machine-block-address-taken, landing-pad, ehfunclet-entry):
+    successors: %bb.5(0x80000000)
+    CLEANUPRET
+
+  bb.5 (landing-pad, ehfunclet-entry):
+    CLEANUPRET
+
+  bb.6:
+    RET 0
+...

``````````

</details>


https://github.com/llvm/llvm-project/pull/77598