From 37e1c88d78ffc49bebf3541af730916343a9ca1e Mon Sep 17 00:00:00 2001
From: herman ten brugge <hermantenbrugge@home.nl>
Date: Sun, 10 Aug 2025 22:02:44 +0200
Subject: [PATCH] Convert float to double for old function code.

---
 tccgen.c                         |  3 +++
 tests/tests2/133_old_func.c      | 23 +++++++++++++++++++++++
 tests/tests2/133_old_func.expect |  2 ++
 3 files changed, 28 insertions(+)
 create mode 100644 tests/tests2/133_old_func.c
 create mode 100644 tests/tests2/133_old_func.expect

diff --git a/tccgen.c b/tccgen.c
index c85db9ee..afb1567a 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -8693,6 +8693,9 @@ static int decl(int l)
 		    if (sym->type.t != VT_VOID)
 		        tcc_error("redefinition of parameter '%s'",
 				  get_tok_str(v, NULL));
+		    if (func_vt.ref->f.func_type == FUNC_OLD &&
+			type.t == VT_FLOAT)
+			type.t = VT_DOUBLE;
 		    convert_parameter_type(&type);
 		    sym->type = type;
 		} else if (type.t & VT_TYPEDEF) {
diff --git a/tests/tests2/133_old_func.c b/tests/tests2/133_old_func.c
new file mode 100644
index 00000000..81b9b75a
--- /dev/null
+++ b/tests/tests2/133_old_func.c
@@ -0,0 +1,23 @@
+int printf(const char *s, ...);
+
+float fx(x)
+float x;
+{
+    return 2.0 * x;
+}
+
+int
+main(void)
+{
+    float fy();
+
+    printf("%g %g\n", fx(2.0), fy(10.0));
+    printf("%g %g\n", fx(2.0f), fy(10.0f));
+}
+
+float fy(x)
+float x;
+{
+    return 3.0 * x;
+}
+
diff --git a/tests/tests2/133_old_func.expect b/tests/tests2/133_old_func.expect
new file mode 100644
index 00000000..e93760b6
--- /dev/null
+++ b/tests/tests2/133_old_func.expect
@@ -0,0 +1,2 @@
+4 30
+4 30