[llvm] [llvm][CodeGen] update live intervals for ModuloScheduleExpanderMVE (PR #132677)

[Hua Tian via llvm-commits]

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@@ -2213,6 +2215,14 @@ void ModuloScheduleExpanderMVE::insertCondBranch(MachineBasicBlock &MBB,
   }
 }
 
+/// Some registers are generated during the kernel expansion. We calculate the
+/// live intervals of these registers after the expansion.
+void ModuloScheduleExpanderMVE::calculateIntervals() {
+  for (Register Reg : NewVRegs)
+    LIS.createAndComputeVirtRegInterval(Reg);
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huaatian wrote:

In some use cases, real live interval information is required. So the previous approach of using createEmptyInterval() carries risks(e.g. https://github.com/llvm/llvm-project/pull/129204). 
I am not sure whether it is safe to skip the calculation, so I chooes to calculte them here. 
Additionally, the number of registers requiring calculation here is not too large.

https://github.com/llvm/llvm-project/pull/132677