diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index e675afca47..e98bed0805 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -322,6 +322,16 @@ static uint8_t cc_op_live(CCOp op)
     g_assert_not_reached();
 }
 
+static MemOp cc_op_size(CCOp op)
+{
+    MemOp size = op & 3;
+
+    assert(op >= CC_OP_FIRST_BWLQ && op <= CC_OP_LAST_BWLQ);
+    assert(size <= MO_TL);
+
+    return size;
+}
+
 static void set_cc_op_1(DisasContext *s, CCOp op, bool dirty)
 {
     int dead;
@@ -884,7 +894,7 @@ static CCPrepare gen_prepare_eflags_c(DisasContext *s, TCGv reg)
     switch (s->cc_op) {
     case CC_OP_SUBB ... CC_OP_SUBQ:
         /* (DATA_TYPE)CC_SRCT < (DATA_TYPE)CC_SRC */
-        size = s->cc_op - CC_OP_SUBB;
+        size = cc_op_size(s->cc_op);
         gen_ext_tl(s->cc_srcT, s->cc_srcT, size, false);
         gen_ext_tl(cpu_cc_src, cpu_cc_src, size, false);
         return (CCPrepare) { .cond = TCG_COND_LTU, .reg = s->cc_srcT,
@@ -892,7 +902,7 @@ static CCPrepare gen_prepare_eflags_c(DisasContext *s, TCGv reg)
 
     case CC_OP_ADDB ... CC_OP_ADDQ:
         /* (DATA_TYPE)CC_DST < (DATA_TYPE)CC_SRC */
-        size = s->cc_op - CC_OP_ADDB;
+        size = cc_op_size(s->cc_op);
         gen_ext_tl(cpu_cc_dst, cpu_cc_dst, size, false);
         gen_ext_tl(cpu_cc_src, cpu_cc_src, size, false);
         return (CCPrepare) { .cond = TCG_COND_LTU, .reg = cpu_cc_dst,
@@ -910,7 +920,7 @@ static CCPrepare gen_prepare_eflags_c(DisasContext *s, TCGv reg)
 
     case CC_OP_SHLB ... CC_OP_SHLQ:
         /* (CC_SRC >> (DATA_BITS - 1)) & 1 */
-        size = s->cc_op - CC_OP_SHLB;
+        size = cc_op_size(s->cc_op);
         return gen_prepare_sign_nz(cpu_cc_src, size);
 
     case CC_OP_MULB ... CC_OP_MULQ:
@@ -918,7 +928,7 @@ static CCPrepare gen_prepare_eflags_c(DisasContext *s, TCGv reg)
                              .reg = cpu_cc_src };
 
     case CC_OP_BMILGB ... CC_OP_BMILGQ:
-        size = s->cc_op - CC_OP_BMILGB;
+        size = cc_op_size(s->cc_op);
         gen_ext_tl(cpu_cc_src, cpu_cc_src, size, false);
         return (CCPrepare) { .cond = TCG_COND_EQ, .reg = cpu_cc_src };
 
@@ -972,10 +982,7 @@ static CCPrepare gen_prepare_eflags_s(DisasContext *s, TCGv reg)
     case CC_OP_POPCNT:
         return (CCPrepare) { .cond = TCG_COND_NEVER };
     default:
-        {
-            MemOp size = (s->cc_op - CC_OP_ADDB) & 3;
-            return gen_prepare_sign_nz(cpu_cc_dst, size);
-        }
+        return gen_prepare_sign_nz(cpu_cc_dst, cc_op_size(s->cc_op));
     }
 }
 
@@ -1016,7 +1023,7 @@ static CCPrepare gen_prepare_eflags_z(DisasContext *s, TCGv reg)
         return (CCPrepare) { .cond = TCG_COND_ALWAYS };
     default:
         {
-            MemOp size = (s->cc_op - CC_OP_ADDB) & 3;
+            MemOp size = cc_op_size(s->cc_op);
             if (size == MO_TL) {
                 return (CCPrepare) { .cond = TCG_COND_EQ, .reg = cpu_cc_dst };
             } else {
@@ -1042,7 +1049,7 @@ static CCPrepare gen_prepare_cc(DisasContext *s, int b, TCGv reg)
     switch (s->cc_op) {
     case CC_OP_SUBB ... CC_OP_SUBQ:
         /* We optimize relational operators for the cmp/jcc case.  */
-        size = s->cc_op - CC_OP_SUBB;
+        size = cc_op_size(s->cc_op);
         switch (jcc_op) {
         case JCC_BE:
             gen_ext_tl(s->cc_srcT, s->cc_srcT, size, false);
@@ -3176,7 +3183,7 @@ static void disas_insn_old(DisasContext *s, CPUState *cpu, int b)
                CC_DST alone, setting CC_SRC, and using a CC_OP_SAR of the
                same width.  */
             tcg_gen_mov_tl(cpu_cc_src, s->tmp4);
-            set_cc_op(s, ((s->cc_op - CC_OP_MULB) & 3) + CC_OP_SARB);
+            set_cc_op(s, CC_OP_SARB + cc_op_size(s->cc_op));
             break;
         default:
             /* Otherwise, generate EFLAGS and replace the C bit.  */
diff --git a/target/i386/tcg/emit.c.inc b/target/i386/tcg/emit.c.inc
index 38b399783e..e9d5d196ce 100644
--- a/target/i386/tcg/emit.c.inc
+++ b/target/i386/tcg/emit.c.inc
@@ -3106,7 +3106,8 @@ static bool gen_eflags_adcox(DisasContext *s, X86DecodedInsn *decode, bool want_
          * bit, we might as well fish CF out of EFLAGS and save a shift.
          */
         if (want_carry && (!need_flags || s->cc_op == CC_OP_SHLB + MO_TL)) {
-            tcg_gen_shri_tl(decode->cc_dst, cpu_cc_src, (8 << (s->cc_op - CC_OP_SHLB)) - 1);
+            MemOp size = cc_op_size(s->cc_op);
+            tcg_gen_shri_tl(decode->cc_dst, cpu_cc_src, (8 << size) - 1);
             got_cf = true;
         }
         gen_mov_eflags(s, decode->cc_src);
