Update zjit/src/backend/lir.rs

Co-authored-by: Takashi Kokubun <[email protected]>

Author: tenderlove

zjit/src/backend/lir.rs

@@ -1751,12 +1751,12 @@ impl Assembler
                 self.expand_branch_insn(insn, &mut insns);
             }
 
-            // If the last instruction of the block is a ret, add a pad patch point after it
-            if let Some(last_insn) = block.insns.last() {
-                if matches!(last_insn, Insn::CRet(_)) {
-                    insns.push(Insn::PadPatchPoint);
-                }
-            }
+            // If the last instruction of the block is a ret, add a pad patch point after it.
+            // Otherwise, because a jump may be longer than a ret, a PatchPoint right before
+            // a ret may overwrite the next block.
+            //
+            // We also need to ensure the current block is long enough to insert a patch point.
+            insns.push(Insn::PadPatchPoint);
         }
         insns
     }