From: Puyan Lotfi <puyan@puyan.org>
Date: Thu, 30 May 2019 21:37:25 +0000 (+0000)
Subject: [MIR-Canon] Fixing case where MachineFunction is empty.
X-Git-Tag: android-x86-9.0-r1~2694
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=6a890853301570f69c567fb2626b492edeb1eaf0;p=android-x86%2Fexternal-llvm.git

[MIR-Canon] Fixing case where MachineFunction is empty.

In cases where the machine function is empty: bail on the RPO traversal.

Differential Revision: https://reviews.llvm.org/D62617



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362158 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/MIRCanonicalizerPass.cpp b/lib/CodeGen/MIRCanonicalizerPass.cpp
index e8a6e409fb5..650240e60fe 100644
--- a/lib/CodeGen/MIRCanonicalizerPass.cpp
+++ b/lib/CodeGen/MIRCanonicalizerPass.cpp
@@ -104,6 +104,8 @@ INITIALIZE_PASS_END(MIRCanonicalizer, "mir-canonicalizer",
                     "Rename Register Operands Canonically", false, false)
 
 static std::vector<MachineBasicBlock *> GetRPOList(MachineFunction &MF) {
+  if (MF.empty())
+    return {};
   ReversePostOrderTraversal<MachineBasicBlock *> RPOT(&*MF.begin());
   std::vector<MachineBasicBlock *> RPOList;
   for (auto MBB : RPOT) {
diff --git a/test/CodeGen/MIR/AArch64/empty-MF.mir b/test/CodeGen/MIR/AArch64/empty-MF.mir
new file mode 100644
index 00000000000..40b1bff06ff
--- /dev/null
+++ b/test/CodeGen/MIR/AArch64/empty-MF.mir
@@ -0,0 +1,11 @@
+# RUN: llc -mtriple aarch64-- -run-pass mir-canonicalizer %s -o - | FileCheck %s
+# CHECK: ...
+# CHECK-NEXT: ---
+# CHECK-NEXT: name:            foo
+# CHECK: body:             |
+# CHECK-EMPTY:
+# CHECK-NEXT: ...
+---
+name: foo
+body:             |
+...