diff --git a/target-alpha/helper.h b/target-alpha/helper.h
index 10c78d0e0e..ccf6a2aae9 100644
--- a/target-alpha/helper.h
+++ b/target-alpha/helper.h
@@ -83,7 +83,6 @@ DEF_HELPER_FLAGS_1(cvtqf, TCG_CALL_CONST, i64, i64)
 DEF_HELPER_FLAGS_1(cvtgf, TCG_CALL_CONST, i64, i64)
 DEF_HELPER_FLAGS_1(cvtgq, TCG_CALL_CONST, i64, i64)
 DEF_HELPER_FLAGS_1(cvtqg, TCG_CALL_CONST, i64, i64)
-DEF_HELPER_FLAGS_1(cvtlq, TCG_CALL_CONST | TCG_CALL_PURE, i64, i64)
 
 DEF_HELPER_FLAGS_1(cvttq, TCG_CALL_CONST, i64, i64)
 DEF_HELPER_FLAGS_1(cvttq_c, TCG_CALL_CONST, i64, i64)
diff --git a/target-alpha/op_helper.c b/target-alpha/op_helper.c
index f9cd07a6ee..a20913033d 100644
--- a/target-alpha/op_helper.c
+++ b/target-alpha/op_helper.c
@@ -1152,13 +1152,6 @@ uint64_t helper_cvtqg (uint64_t a)
     return float64_to_g(fr);
 }
 
-uint64_t helper_cvtlq (uint64_t a)
-{
-    int32_t lo = a >> 29;
-    int32_t hi = a >> 32;
-    return (lo & 0x3FFFFFFF) | (hi & 0xc0000000);
-}
-
 /* PALcode support special instructions */
 #if !defined (CONFIG_USER_ONLY)
 void helper_hw_rei (void)
diff --git a/target-alpha/translate.c b/target-alpha/translate.c
index 1c296cfbb4..d7591cc9bd 100644
--- a/target-alpha/translate.c
+++ b/target-alpha/translate.c
@@ -598,6 +598,28 @@ static inline void gen_fp_exc_raise(int rc, int fn11)
     gen_fp_exc_raise_ignore(rc, fn11, fn11 & QUAL_I ? 0 : float_flag_inexact);
 }
 
+static void gen_fcvtlq(int rb, int rc)
+{
+    if (unlikely(rc == 31)) {
+        return;
+    }
+    if (unlikely(rb == 31)) {
+        tcg_gen_movi_i64(cpu_fir[rc], 0);
+    } else {
+        TCGv tmp = tcg_temp_new();
+
+        /* The arithmetic right shift here, plus the sign-extended mask below
+           yields a sign-extended result without an explicit ext32s_i64.  */
+        tcg_gen_sari_i64(tmp, cpu_fir[rb], 32);
+        tcg_gen_shri_i64(cpu_fir[rc], cpu_fir[rb], 29);
+        tcg_gen_andi_i64(tmp, tmp, (int32_t)0xc0000000);
+        tcg_gen_andi_i64(cpu_fir[rc], cpu_fir[rc], 0x3fffffff);
+        tcg_gen_or_i64(cpu_fir[rc], cpu_fir[rc], tmp);
+
+        tcg_temp_free(tmp);
+    }
+}
+
 static void gen_fcvtql(int rb, int rc)
 {
     if (unlikely(rc == 31)) {
@@ -647,7 +669,6 @@ static inline void glue(gen_f, name)(int rb, int rc)    \
         tcg_temp_free(tmp);                             \
     }                                                   \
 }
-FARITH2(cvtlq)
 
 /* ??? VAX instruction qualifiers ignored.  */
 FARITH2(sqrtf)