[PATCH olang v2 4/4] codegen: x86_64: add if cond support for literals

[Johnny Richard <johnny@johnnyrichard.com>]

We are not optimizing the assembly code, so every literal statement will
emit a `cmp` instruction in order achieve if condition support for
literals.

Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>
---
 src/codegen_linux_x86_64.c                    |  1 +
 .../tests/0022_if_statement_literal.ol        | 24 +++++++++++++++++++
 2 files changed, 25 insertions(+)
 create mode 100644 tests/integration/tests/0022_if_statement_literal.ol

diff --git a/src/codegen_linux_x86_64.c b/src/codegen_linux_x86_64.c
index 3b509ba..958c46e 100644
--- a/src/codegen_linux_x86_64.c
+++ b/src/codegen_linux_x86_64.c
@@ -328,6 +328,7 @@ codegen_linux_x86_64_emit_block(FILE *out, ast_block_t *block)
                 size_t end_if_label = codegen_linux_x86_64_get_next_label();
 
                 codegen_linux_x86_64_emit_expression(out, cond);
+                fprintf(out, "    cmp $1, %%rax\n");
                 fprintf(out, "    jnz .L%ld\n", end_if_label);
 
                 assert(then->kind == AST_NODE_BLOCK && "invalid if-then block");
diff --git a/tests/integration/tests/0022_if_statement_literal.ol b/tests/integration/tests/0022_if_statement_literal.ol
new file mode 100644
index 0000000..3ae6ef3
--- /dev/null
+++ b/tests/integration/tests/0022_if_statement_literal.ol
@@ -0,0 +1,24 @@
+# Copyright (C) 2024 olang mantainers
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+fn main(): u32 {
+  if 1 {
+    return 0
+  }
+  return 1
+}
+
+# TEST test_compile(exit_code=0)
+# TEST test_run_binary(exit_code=0)
-- 
2.46.0