diff --git a/src/emulate.c b/src/emulate.c
index cd1a0bd25..b2d77f63e 100644
--- a/src/emulate.c
+++ b/src/emulate.c
@@ -926,6 +926,7 @@ static void match_pattern(block_t *block)
                 ir->rs2 = next_ir->rd;
                 ir->rs1 = next_ir->rs1;
                 ir->impl = dispatch_table[ir->opcode];
+                ir->tailcall = next_ir->tailcall;
             } else if (next_ir->opcode == rv_insn_add &&
                        ir->rd == next_ir->rs1) {
                 /* The destination register of the LUI instruction is the
@@ -935,21 +936,22 @@ static void match_pattern(block_t *block)
                 ir->rs2 = next_ir->rd;
                 ir->rs1 = next_ir->rs2;
                 ir->impl = dispatch_table[ir->opcode];
-            } else {
+                ir->tailcall = next_ir->tailcall;
+            } else if (next_ir->opcode == rv_insn_lui) {
                 count = 1;
-                next_ir = ir + 1;
                 while (1) {
                     if (next_ir->opcode != rv_insn_lui)
                         break;
                     next_ir->opcode = rv_insn_nop;
                     count++;
-                    next_ir += 1;
-                }
-                if (count > 1) {
-                    ir->imm2 = count;
-                    ir->opcode = rv_insn_fuse1;
-                    ir->impl = dispatch_table[ir->opcode];
+                    if (next_ir->tailcall)
+                        break;
+                    next_ir++;
                 }
+                ir->imm2 = count;
+                ir->opcode = rv_insn_fuse1;
+                ir->impl = dispatch_table[ir->opcode];
+                ir->tailcall = next_ir->tailcall;
             }
             break;
 
diff --git a/src/rv32_constopt.c b/src/rv32_constopt.c
index af9e92213..a2ec2b0ce 100644
--- a/src/rv32_constopt.c
+++ b/src/rv32_constopt.c
@@ -443,8 +443,8 @@ CONSTOPT(mulh, {
     if (constopt_info->is_constant[ir->rs1] &&
         constopt_info->is_constant[ir->rs2]) {
         constopt_info->is_constant[ir->rd] = true;
-        const int64_t a = constopt_info->const_val[ir->rs1];
-        const int64_t b = constopt_info->const_val[ir->rs2];
+        const int64_t a = (int32_t) constopt_info->const_val[ir->rs1];
+        const int64_t b = (int32_t) constopt_info->const_val[ir->rs2];
         ir->imm = ((uint64_t) (a * b)) >> 32;
         constopt_info->const_val[ir->rd] = ir->imm;
         ir->opcode = rv_insn_lui;
@@ -457,7 +457,6 @@ CONSTOPT(mulh, {
 CONSTOPT(mulhsu, {
     if (constopt_info->is_constant[ir->rs1] &&
         constopt_info->is_constant[ir->rs2]) {
-        printf("OPT MUL\n");
         constopt_info->is_constant[ir->rd] = true;
         const int64_t a = (int32_t) constopt_info->const_val[ir->rs1];
         const int64_t b = constopt_info->const_val[ir->rs2];
@@ -757,7 +756,7 @@ CONSTOPT(csw, {})
 CONSTOPT(caddi, {
     if (constopt_info->is_constant[ir->rd]) {
         constopt_info->is_constant[ir->rd] = true;
-        ir->imm = constopt_info->const_val[ir->rd] + (uint16_t) ir->imm;
+        ir->imm = constopt_info->const_val[ir->rd] + (int16_t) ir->imm;
         constopt_info->const_val[ir->rd] = ir->imm;
         ir->opcode = rv_insn_clui;
         ir->impl = dispatch_table[ir->opcode];
@@ -768,7 +767,7 @@ CONSTOPT(caddi, {
 /* C.JAL */
 CONSTOPT(cjal, {
     constopt_info->is_constant[rv_reg_ra] = true;
-    constopt_info->const_val[ir->rd] = ir->pc + ir->insn_len;
+    constopt_info->const_val[rv_reg_ra] = ir->pc + ir->insn_len;
 })
 
 /* C.LI loads the sign-extended 6-bit immediate, imm, into register rd.
@@ -817,7 +816,8 @@ CONSTOPT(csrli, {
     if (constopt_info->is_constant[ir->rs1]) {
         constopt_info->is_constant[ir->rs1] = true;
         ir->imm = constopt_info->const_val[ir->rs1] >> ir->shamt;
-        constopt_info->const_val[ir->rd] = ir->imm;
+        constopt_info->const_val[ir->rs1] = ir->imm;
+        ir->rd = ir->rs1;
         ir->opcode = rv_insn_clui;
         ir->impl = dispatch_table[ir->opcode];
     } else
@@ -834,7 +834,8 @@ CONSTOPT(csrai, {
         ir->imm = constopt_info->const_val[ir->rs1] >> ir->shamt;
         for (unsigned int i = 0; i < ir->shamt; ++i)
             ir->imm |= mask >> i;
-        constopt_info->const_val[ir->rd] = ir->imm;
+        constopt_info->const_val[ir->rs1] = ir->imm;
+        ir->rd = ir->rs1;
         ir->opcode = rv_insn_clui;
         ir->impl = dispatch_table[ir->opcode];
     } else
@@ -848,8 +849,9 @@ CONSTOPT(csrai, {
 CONSTOPT(candi, {
     if (constopt_info->is_constant[ir->rs1]) {
         constopt_info->is_constant[ir->rs1] = true;
-        ir->imm = constopt_info->const_val[ir->rs1] & ir->shamt;
-        constopt_info->const_val[ir->rd] = ir->imm;
+        ir->imm = constopt_info->const_val[ir->rs1] & ir->imm;
+        constopt_info->const_val[ir->rs1] = ir->imm;
+        ir->rd = ir->rs1;
         ir->opcode = rv_insn_clui;
         ir->impl = dispatch_table[ir->opcode];
     } else
@@ -948,7 +950,7 @@ CONSTOPT(cbnez, {
 CONSTOPT(cslli, {
     if (constopt_info->is_constant[ir->rd]) {
         constopt_info->is_constant[ir->rd] = true;
-        ir->imm = constopt_info->const_val[ir->rs2] << (uint8_t) ir->imm;
+        ir->imm = constopt_info->const_val[ir->rd] << (uint8_t) ir->imm;
         constopt_info->const_val[ir->rd] = ir->imm;
         ir->opcode = rv_insn_clui;
         ir->impl = dispatch_table[ir->opcode];