[llvm] [RISCV] Separate doLocalPostpass into new pass and move to post vector regalloc (PR #88295)

[Luke Lau via llvm-commits]

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@@ -1510,7 +1545,10 @@ static bool canMutatePriorConfig(const MachineInstr &PrevMI,
 
     auto &AVL = MI.getOperand(1);
     auto &PrevAVL = PrevMI.getOperand(1);
-    assert(MRI.isSSA());
+    assert(!AVL.isReg() || !AVL.getReg().isVirtual() ||
+           MRI.hasOneDef(AVL.getReg()));
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lukel97 wrote:

I was able to create an .mir test case that fails this assertion at least. I think it should be ok if we just return false if there's more than one def?

https://github.com/llvm/llvm-project/pull/88295