diff --git a/disas/riscv.c b/disas/riscv.c
index 59a9b0437a..d373127055 100644
--- a/disas/riscv.c
+++ b/disas/riscv.c
@@ -504,14 +504,19 @@ typedef struct {
     const rvc_constraint *constraints;
 } rv_comp_data;
 
+enum {
+    rvcd_imm_nz = 0x1
+};
+
 typedef struct {
     const char * const name;
     const rv_codec codec;
     const char * const format;
     const rv_comp_data *pseudo;
-    const int decomp_rv32;
-    const int decomp_rv64;
-    const int decomp_rv128;
+    const short decomp_rv32;
+    const short decomp_rv64;
+    const short decomp_rv128;
+    const short decomp_data;
 } rv_opcode_data;
 
 /* register names */
@@ -1011,7 +1016,8 @@ const rv_opcode_data opcode_data[] = {
     { "fcvt.q.lu", rv_codec_r_m, rv_fmt_rm_frd_rs1, NULL, 0, 0, 0 },
     { "fmv.x.q", rv_codec_r, rv_fmt_rd_frs1, NULL, 0, 0, 0 },
     { "fmv.q.x", rv_codec_r, rv_fmt_frd_rs1, NULL, 0, 0, 0 },
-    { "c.addi4spn", rv_codec_ciw_4spn, rv_fmt_rd_rs1_imm, NULL, rv_op_addi, rv_op_addi, rv_op_addi },
+    { "c.addi4spn", rv_codec_ciw_4spn, rv_fmt_rd_rs1_imm, NULL, rv_op_addi,
+      rv_op_addi, rv_op_addi, rvcd_imm_nz },
     { "c.fld", rv_codec_cl_ld, rv_fmt_frd_offset_rs1, NULL, rv_op_fld, rv_op_fld, 0 },
     { "c.lw", rv_codec_cl_lw, rv_fmt_rd_offset_rs1, NULL, rv_op_lw, rv_op_lw, rv_op_lw },
     { "c.flw", rv_codec_cl_lw, rv_fmt_frd_offset_rs1, NULL, rv_op_flw, 0, 0 },
@@ -1019,14 +1025,20 @@ const rv_opcode_data opcode_data[] = {
     { "c.sw", rv_codec_cs_sw, rv_fmt_rs2_offset_rs1, NULL, rv_op_sw, rv_op_sw, rv_op_sw },
     { "c.fsw", rv_codec_cs_sw, rv_fmt_frs2_offset_rs1, NULL, rv_op_fsw, 0, 0 },
     { "c.nop", rv_codec_ci_none, rv_fmt_none, NULL, rv_op_addi, rv_op_addi, rv_op_addi },
-    { "c.addi", rv_codec_ci, rv_fmt_rd_rs1_imm, NULL, rv_op_addi, rv_op_addi, rv_op_addi },
+    { "c.addi", rv_codec_ci, rv_fmt_rd_rs1_imm, NULL, rv_op_addi, rv_op_addi,
+      rv_op_addi, rvcd_imm_nz },
     { "c.jal", rv_codec_cj_jal, rv_fmt_rd_offset, NULL, rv_op_jal, 0, 0 },
     { "c.li", rv_codec_ci_li, rv_fmt_rd_rs1_imm, NULL, rv_op_addi, rv_op_addi, rv_op_addi },
-    { "c.addi16sp", rv_codec_ci_16sp, rv_fmt_rd_rs1_imm, NULL, rv_op_addi, rv_op_addi, rv_op_addi },
-    { "c.lui", rv_codec_ci_lui, rv_fmt_rd_imm, NULL, rv_op_lui, rv_op_lui, rv_op_lui },
-    { "c.srli", rv_codec_cb_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_srli, rv_op_srli, rv_op_srli },
-    { "c.srai", rv_codec_cb_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_srai, rv_op_srai, rv_op_srai },
-    { "c.andi", rv_codec_cb_imm, rv_fmt_rd_rs1_imm, NULL, rv_op_andi, rv_op_andi, rv_op_andi },
+    { "c.addi16sp", rv_codec_ci_16sp, rv_fmt_rd_rs1_imm, NULL, rv_op_addi,
+      rv_op_addi, rv_op_addi, rvcd_imm_nz },
+    { "c.lui", rv_codec_ci_lui, rv_fmt_rd_imm, NULL, rv_op_lui, rv_op_lui,
+      rv_op_lui, rvcd_imm_nz },
+    { "c.srli", rv_codec_cb_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_srli,
+      rv_op_srli, rv_op_srli, rvcd_imm_nz },
+    { "c.srai", rv_codec_cb_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_srai,
+      rv_op_srai, rv_op_srai, rvcd_imm_nz },
+    { "c.andi", rv_codec_cb_imm, rv_fmt_rd_rs1_imm, NULL, rv_op_andi,
+      rv_op_andi, rv_op_andi, rvcd_imm_nz },
     { "c.sub", rv_codec_cs, rv_fmt_rd_rs1_rs2, NULL, rv_op_sub, rv_op_sub, rv_op_sub },
     { "c.xor", rv_codec_cs, rv_fmt_rd_rs1_rs2, NULL, rv_op_xor, rv_op_xor, rv_op_xor },
     { "c.or", rv_codec_cs, rv_fmt_rd_rs1_rs2, NULL, rv_op_or, rv_op_or, rv_op_or },
@@ -1036,7 +1048,8 @@ const rv_opcode_data opcode_data[] = {
     { "c.j", rv_codec_cj, rv_fmt_rd_offset, NULL, rv_op_jal, rv_op_jal, rv_op_jal },
     { "c.beqz", rv_codec_cb, rv_fmt_rs1_rs2_offset, NULL, rv_op_beq, rv_op_beq, rv_op_beq },
     { "c.bnez", rv_codec_cb, rv_fmt_rs1_rs2_offset, NULL, rv_op_bne, rv_op_bne, rv_op_bne },
-    { "c.slli", rv_codec_ci_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_slli, rv_op_slli, rv_op_slli },
+    { "c.slli", rv_codec_ci_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_slli,
+      rv_op_slli, rv_op_slli, rvcd_imm_nz },
     { "c.fldsp", rv_codec_ci_ldsp, rv_fmt_frd_offset_rs1, NULL, rv_op_fld, rv_op_fld, rv_op_fld },
     { "c.lwsp", rv_codec_ci_lwsp, rv_fmt_rd_offset_rs1, NULL, rv_op_lw, rv_op_lw, rv_op_lw },
     { "c.flwsp", rv_codec_ci_lwsp, rv_fmt_frd_offset_rs1, NULL, rv_op_flw, 0, 0 },
@@ -2795,8 +2808,13 @@ static void decode_inst_decompress_rv32(rv_decode *dec)
 {
     int decomp_op = opcode_data[dec->op].decomp_rv32;
     if (decomp_op != rv_op_illegal) {
-        dec->op = decomp_op;
-        dec->codec = opcode_data[decomp_op].codec;
+        if ((opcode_data[dec->op].decomp_data & rvcd_imm_nz)
+            && dec->imm == 0) {
+            dec->op = rv_op_illegal;
+        } else {
+            dec->op = decomp_op;
+            dec->codec = opcode_data[decomp_op].codec;
+        }
     }
 }
 
@@ -2804,8 +2822,13 @@ static void decode_inst_decompress_rv64(rv_decode *dec)
 {
     int decomp_op = opcode_data[dec->op].decomp_rv64;
     if (decomp_op != rv_op_illegal) {
-        dec->op = decomp_op;
-        dec->codec = opcode_data[decomp_op].codec;
+        if ((opcode_data[dec->op].decomp_data & rvcd_imm_nz)
+            && dec->imm == 0) {
+            dec->op = rv_op_illegal;
+        } else {
+            dec->op = decomp_op;
+            dec->codec = opcode_data[decomp_op].codec;
+        }
     }
 }
 
@@ -2813,8 +2836,13 @@ static void decode_inst_decompress_rv128(rv_decode *dec)
 {
     int decomp_op = opcode_data[dec->op].decomp_rv128;
     if (decomp_op != rv_op_illegal) {
-        dec->op = decomp_op;
-        dec->codec = opcode_data[decomp_op].codec;
+        if ((opcode_data[dec->op].decomp_data & rvcd_imm_nz)
+            && dec->imm == 0) {
+            dec->op = rv_op_illegal;
+        } else {
+            dec->op = decomp_op;
+            dec->codec = opcode_data[decomp_op].codec;
+        }
     }
 }