Consistently use 64 bit constants for 64 bit IR instructions.

Thanks to Peter Cawley. #1084

1 files changed, 2 insertions, 1 deletions

diff --git a/src/lj_asm_x86.h b/src/lj_asm_x86.h
index 9f779bf5..c92de3d8 100644
--- a/src/lj_asm_x86.h
+++ b/src/lj_asm_x86.h
@@ -140,7 +140,8 @@ static IRRef asm_fuseabase(ASMState *as, IRRef ref)
     }
   } else if (irb->o == IR_ADD && irref_isk(irb->op2)) {
     /* Fuse base offset (vararg load). */
-    as->mrm.ofs = IR(irb->op2)->i;
+    IRIns *irk = IR(irb->op2);
+    as->mrm.ofs = irk->o == IR_KINT ? irk->i : (int32_t)ir_kint64(irk)->u64;
     return irb->op1;
   }
   return ref;  /* Otherwise use the given array base. */