Index: llvm/lib/Target/RISCV/RISCVExpandAtomicPseudoInsts.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVExpandAtomicPseudoInsts.cpp
+++ llvm/lib/Target/RISCV/RISCVExpandAtomicPseudoInsts.cpp
@@ -64,9 +64,21 @@
 
 bool RISCVExpandAtomicPseudo::runOnMachineFunction(MachineFunction &MF) {
   TII = static_cast<const RISCVInstrInfo *>(MF.getSubtarget().getInstrInfo());
+
+  unsigned OldSize = 0;
+  for (auto &MBB : MF)
+    for (auto &MI : MBB)
+      OldSize += TII->getInstSizeInBytes(MI);
+
   bool Modified = false;
   for (auto &MBB : MF)
     Modified |= expandMBB(MBB);
+
+  unsigned NewSize = 0;
+  for (auto &MBB : MF)
+    for (auto &MI : MBB)
+      NewSize += TII->getInstSizeInBytes(MI);
+  assert(OldSize >= NewSize);
   return Modified;
 }
 
Index: llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp
+++ llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp
@@ -56,9 +56,21 @@
 
 bool RISCVExpandPseudo::runOnMachineFunction(MachineFunction &MF) {
   TII = static_cast<const RISCVInstrInfo *>(MF.getSubtarget().getInstrInfo());
+
+  unsigned OldSize = 0;
+  for (auto &MBB : MF)
+    for (auto &MI : MBB)
+      OldSize += TII->getInstSizeInBytes(MI);
+
   bool Modified = false;
   for (auto &MBB : MF)
     Modified |= expandMBB(MBB);
+
+  unsigned NewSize = 0;
+  for (auto &MBB : MF)
+    for (auto &MI : MBB)
+      NewSize += TII->getInstSizeInBytes(MI);
+  assert(OldSize >= NewSize);
   return Modified;
 }
 
@@ -277,9 +289,21 @@
 
 bool RISCVPreRAExpandPseudo::runOnMachineFunction(MachineFunction &MF) {
   TII = static_cast<const RISCVInstrInfo *>(MF.getSubtarget().getInstrInfo());
+
+  unsigned OldSize = 0;
+  for (auto &MBB : MF)
+    for (auto &MI : MBB)
+      OldSize += TII->getInstSizeInBytes(MI);
+
   bool Modified = false;
   for (auto &MBB : MF)
     Modified |= expandMBB(MBB);
+
+  unsigned NewSize = 0;
+  for (auto &MBB : MF)
+    for (auto &MI : MBB)
+      NewSize += TII->getInstSizeInBytes(MI);
+  assert(OldSize >= NewSize);
   return Modified;
 }