[llvm] [llvm] Support multiple save/restore points in mir (PR #119357)

[Philip Reames via llvm-commits]

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@@ -1077,6 +1075,41 @@ bool MIRParserImpl::initializeConstantPool(PerFunctionMIParsingState &PFS,
   return false;
 }
 
+// Return true if basic block was incorrectly specified in MIR
+bool MIRParserImpl::initializeSaveRestorePoints(
+    PerFunctionMIParsingState &PFS, const yaml::SaveRestorePoints &YamlSRPoints,
+    bool IsSavePoints) {
+  MachineBasicBlock *MBB = nullptr;
+  if (std::holds_alternative<std::vector<yaml::SaveRestorePointEntry>>(
+          YamlSRPoints)) {
+    const auto &VectorRepr =
+        std::get<std::vector<yaml::SaveRestorePointEntry>>(YamlSRPoints);
+    if (VectorRepr.empty())
+      return false;
+
+    const auto &Entry = VectorRepr.front();
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preames wrote:

Unless I'm missing something from the code structure, you're only parsing the first bb reference here.  Also, you don't seem to have any tests for round tripping MIR with multiple save restore points.

https://github.com/llvm/llvm-project/pull/119357