From fd6d2180c5c801bb0b4c5dde27d61503059fc97d Mon Sep 17 00:00:00 2001
From: herman ten brugge <hermantenbrugge@home.nl>
Date: Mon, 31 Jul 2023 09:24:06 +0200
Subject: [PATCH] Align stack when returning structs.

The stack was not aligned when a returned structure was stored on stack.
This resulted in destoying of previous values stored on stack.
See testcase 119 (tst_struct_return_align) where value d is overwritten.
---
 tccgen.c                             |  3 ++-
 tests/tests2/119_random_stuff.c      | 21 +++++++++++++++++++++
 tests/tests2/119_random_stuff.expect |  1 +
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/tccgen.c b/tccgen.c
index f91a43dd..d5e3b15f 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -6142,6 +6142,7 @@ special_math_val:
                        space.  Assume register size is power of 2.  */
                     if (regsize > align)
                       align = regsize;
+		    loc &= -align;
                     loc = (loc - size) & -align;
                     addr = loc;
                     offset = 0;
@@ -6622,7 +6623,7 @@ static void gfunc_return(CType *func_type)
             size = type_size(func_type,&align);
             if ((vtop->r != (VT_LOCAL | VT_LVAL) ||
                  (vtop->c.i & (ret_align-1)))
-                || (align & (ret_align-1))) {
+                && (align & (ret_align-1))) {
                 loc = (loc - size) & -ret_align;
                 addr = loc;
                 type = *func_type;
diff --git a/tests/tests2/119_random_stuff.c b/tests/tests2/119_random_stuff.c
index 0b7a4e50..5530c096 100644
--- a/tests/tests2/119_random_stuff.c
+++ b/tests/tests2/119_random_stuff.c
@@ -99,6 +99,26 @@ void tst_indir_func(void)
     tst_indir.print("tst_indir_func %d\n", 10);
 }
 
+struct V {
+  int x, y, z;
+};
+
+struct V vec(void)
+{
+  return (struct V) { 1, 2, 3 };
+}
+
+void func(float f, struct V v)
+{
+  printf("%g\n", f);
+}
+
+void tst_struct_return_align(void)
+{
+  float d = 5.0f;
+  func(d, vec());
+}
+
 int
 main (void)
 {
@@ -117,4 +137,5 @@ main (void)
   tst_pack();
   tst_cast();
   tst_indir_func();
+  tst_struct_return_align();
 }
diff --git a/tests/tests2/119_random_stuff.expect b/tests/tests2/119_random_stuff.expect
index 3bd4a87a..02ce2282 100644
--- a/tests/tests2/119_random_stuff.expect
+++ b/tests/tests2/119_random_stuff.expect
@@ -4,3 +4,4 @@ tst_compare: ok
 tst_pack: j.f = 5, i.f = 5
 schar to ushort cast: ffff0033
 tst_indir_func 10
+5