diff --git a/qemu/target/arm/vec_helper.c b/qemu/target/arm/vec_helper.c
index 00f6e8b3..88681e2b 100644
--- a/qemu/target/arm/vec_helper.c
+++ b/qemu/target/arm/vec_helper.c
@@ -294,7 +294,7 @@ void HELPER(gvec_sdot_idx_b)(void *vd, void *vn, void *vm, uint32_t desc)
     intptr_t index = simd_data(desc);
     uint32_t *d = vd;
     int8_t *n = vn;
-    int8_t *m_indexed = (int8_t *)vm + index * 4;
+    int8_t *m_indexed = (int8_t *)vm + H4(index) * 4;
 
     /* Notice the special case of opr_sz == 8, from aa64/aa32 advsimd.
      * Otherwise opr_sz is a multiple of 16.
@@ -325,7 +325,7 @@ void HELPER(gvec_udot_idx_b)(void *vd, void *vn, void *vm, uint32_t desc)
     intptr_t index = simd_data(desc);
     uint32_t *d = vd;
     uint8_t *n = vn;
-    uint8_t *m_indexed = (uint8_t *)vm + index * 4;
+    uint8_t *m_indexed = (uint8_t *)vm + H4(index) * 4;
 
     /* Notice the special case of opr_sz == 8, from aa64/aa32 advsimd.
      * Otherwise opr_sz is a multiple of 16.