Implement type conversion in code generation

- Add OP_cast instruction for type conversions
- Implement cast support in ARM backend
- Implement cast support in RISC-V backend
- Add cast handling in SSA and register allocation
- Code formatted with clang-format-18

Author: jserv

src/arm-codegen.c

@@ -125,6 +125,9 @@ void update_elf_offset(ph2_ir_t *ph2_ir)
     case OP_sign_ext:
         elf_offset += 4;
         return;
+    case OP_cast:
+        elf_offset += 4;
+        return;
     default:
         fatal("Unknown opcode");
     }
@@ -439,6 +442,10 @@ void emit_ph2_ir(ph2_ir_t *ph2_ir)
         /* TODO: Allow to sign extends to other types */
         emit(__sxtb(__AL, rd, rn, 0));
         return;
+    case OP_cast:
+        /* Generic cast operation - for now, just move the value */
+        emit(__mov_r(__AL, rd, rn));
+        return;
     default:
         fatal("Unknown opcode");
     }

src/reg-alloc.c

@@ -596,6 +596,7 @@ void reg_alloc(void)
                     break;
                 case OP_trunc:
                 case OP_sign_ext:
+                case OP_cast:
                     src0 = prepare_operand(bb, insn->rs1, -1);
                     dest = prepare_dest(bb, insn->rd, src0, -1);
                     ir = bb_add_ph2_ir(bb, insn->opcode);
@@ -787,6 +788,9 @@ void dump_ph2_ir(void)
         case OP_sign_ext:
             printf("\t%%x%c = sign_ext %%x%c, %d", rd, rs1, ph2_ir->src1);
             break;
+        case OP_cast:
+            printf("\t%%x%c = cast %%x%c", rd, rs1);
+            break;
         default:
             break;
         }

src/riscv-codegen.c

@@ -99,6 +99,9 @@ void update_elf_offset(ph2_ir_t *ph2_ir)
     case OP_sign_ext:
         elf_offset += 12;
         return;
+    case OP_cast:
+        elf_offset += 4;
+        return;
     default:
         fatal("Unknown opcode");
     }
@@ -422,6 +425,10 @@ void emit_ph2_ir(ph2_ir_t *ph2_ir)
         /* TODO: Allow user to switch to Zbb extension if needed */
         /* emit(__sext_b(rd, rs1)); */
         return;
+    case OP_cast:
+        /* Generic cast operation - for now, just move the value */
+        emit(__addi(rd, rs1, 0));
+        return;
     default:
         fatal("Unknown opcode");
     }

src/ssa.c

@@ -1119,6 +1119,11 @@ void bb_dump(FILE *fd, func_t *func, basic_block_t *bb)
                         insn->rd->var_name, insn->rd->subscript,
                         insn->rs1->var_name, insn->rs1->subscript, insn->sz);
                 break;
+            case OP_cast:
+                sprintf(str, "<%s<SUB>%d</SUB> := cast %s<SUB>%d</SUB>>",
+                        insn->rd->var_name, insn->rd->subscript,
+                        insn->rs1->var_name, insn->rs1->subscript);
+                break;
             default:
                 printf("Unknown opcode\n");
                 abort();