[RISCV] Update LiveIntervals before erasing instr in RISCVInsertVSETVLI

lukel97 · lukel97 · commit d03e8120577a · 2024-07-01T14:02:48.000+08:00
Hopefully fixes a use-after-poison reported from the asan buildbots. I
wasn't able to recreate the assertion locally though.
diff --git a/llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp b/llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
@@ -1704,11 +1704,11 @@ void RISCVInsertVSETVLI::coalesceVSETVLIs(MachineBasicBlock &MBB) const {
             MachineInstr *VLOpDef = MRI->getUniqueVRegDef(OldVLReg);
             if (VLOpDef && TII->isAddImmediate(*VLOpDef, OldVLReg) &&
                 MRI->use_nodbg_empty(OldVLReg)) {
-              VLOpDef->eraseFromParent();
               if (LIS) {
                 LIS->removeInterval(OldVLReg);
                 LIS->RemoveMachineInstrFromMaps(*VLOpDef);
               }
+              VLOpDef->eraseFromParent();
             }
           }
           MI.setDesc(NextMI->getDesc());

Original file line number	Diff line number	Diff line change
`@@ -1704,11 +1704,11 @@ void RISCVInsertVSETVLI::coalesceVSETVLIs(MachineBasicBlock &MBB) const {`
`1704`	`1704`	`MachineInstr *VLOpDef = MRI->getUniqueVRegDef(OldVLReg);`
`1705`	`1705`	`if (VLOpDef && TII->isAddImmediate(*VLOpDef, OldVLReg) &&`
`1706`	`1706`	`MRI->use_nodbg_empty(OldVLReg)) {`
`1707`		`- VLOpDef->eraseFromParent();`
`1708`	`1707`	`if (LIS) {`
`1709`	`1708`	`LIS->removeInterval(OldVLReg);`
`1710`	`1709`	`LIS->RemoveMachineInstrFromMaps(*VLOpDef);`
`1711`	`1710`	`}`
	`1711`	`+ VLOpDef->eraseFromParent();`
`1712`	`1712`	`}`
`1713`	`1713`	`}`
`1714`	`1714`	`MI.setDesc(NextMI->getDesc());`