[llvm] [RISCV] Don't use MachineInstr::isIdenticalTo in hasSameAVL (PR #90431)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-risc-v

Author: Luke Lau (lukel97)

<details>
<summary>Changes</summary>

MachineInstr::isIdenticalTo compares that the operands and flags are the same IIUC, but I think we actually want to check that it's the same MachineInstr * with respect to position in the block etc.


---
Full diff: https://github.com/llvm/llvm-project/pull/90431.diff


1 Files Affected:

- (modified) llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp (+2-2) 


``````````diff
diff --git a/llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp b/llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
index b5fd508fa77de2..b27e1dd258ebd0 100644
--- a/llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
+++ b/llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
@@ -568,8 +568,8 @@ class VSETVLIInfo {
 
   bool hasSameAVL(const VSETVLIInfo &Other) const {
     if (hasAVLReg() && Other.hasAVLReg())
-      return getAVLDefMI().isIdenticalTo(Other.getAVLDefMI()) &&
-             getAVLReg() == Other.getAVLReg();
+      return AVLRegDef.DefMI == Other.AVLRegDef.DefMI &&
+             AVLRegDef.DefReg == Other.AVLRegDef.DefReg;
 
     if (hasAVLImm() && Other.hasAVLImm())
       return getAVLImm() == Other.getAVLImm();

``````````

</details>


https://github.com/llvm/llvm-project/pull/90431