testsuite: Add further zero size elt passing tests [PR102024]

As discussed in PR102024, zero width bitfields might not be the only ones
causing ABI issues at least on mips, zero size arrays or (in C only) zero
sized (empty) structures can be problematic too.

The following patch adds some coverage for it too.

Tested on x86_64-linux with
make check-gcc check-g++ RUNTESTFLAGS='ALT_CC_UNDER_TEST=gcc ALT_CXX_UNDER_TEST=g++ --target_board=unix\{-m32,-m64\} compat.exp=pr102024*'
make check-gcc check-g++ RUNTESTFLAGS='ALT_CC_UNDER_TEST=clang ALT_CXX_UNDER_TEST=clang++ --target_board=unix\{-m32,-m64\} compat.exp=pr102024*'
with gcc/g++ 10.3 and clang 11.  Everything but (expectedly)
FAIL: gcc.dg/compat/pr102024 c_compat_x_tst.o-c_compat_y_alt.o execute
FAIL: gcc.dg/compat/pr102024 c_compat_x_alt.o-c_compat_y_tst.o execute
for -m64 ALT_CC_UNDER_TEST=gcc passes.

2022-04-01  Jakub Jelinek  <jakub@redhat.com>

	PR target/102024
	* gcc.dg/compat/pr102024_test.h: Add further tests with zero sized
	structures and arrays.
	* g++.dg/compat/pr102024_test.h: Add further tests with zero sized
	arrays.

2 files changed, 12 insertions, 0 deletions

diff --git a/gcc/testsuite/g++.dg/compat/pr102024_test.h b/gcc/testsuite/g++.dg/compat/pr102024_test.h
index d8f4103..488a8ea 100644
--- a/gcc/testsuite/g++.dg/compat/pr102024_test.h
+++ b/gcc/testsuite/g++.dg/compat/pr102024_test.h
@@ -4,3 +4,9 @@ T(2,int:0;float a;,F(2,a,2.25f,16.5f))
 T(3,double a;long long:0;double b;,F(3,a,42.0,43.125)F(3,b,-17.5,35.75))
 T(4,double a;long long:0;,F(4,a,1.0,17.125))
 T(5,long long:0;double a;,F(5,a,2.25,16.5))
+T(6,float a;struct{}b[0];float c;,F(6,a,42.0f,43.125f)F(6,c,-17.5f,35.75f))
+T(7,float a;struct{}b[0];;,F(7,a,1.0f,17.125f))
+T(8,int a[0];float b;,F(8,b,2.25f,16.5f))
+T(9,double a;long long b[0];double c;,F(9,a,42.0,43.125)F(9,c,-17.5,35.75))
+T(10,double a;struct{}b[0];,F(10,a,1.0,17.125))
+T(11,struct{}a[0];double b;,F(11,b,2.25,16.5))
diff --git a/gcc/testsuite/gcc.dg/compat/pr102024_test.h b/gcc/testsuite/gcc.dg/compat/pr102024_test.h
index d8f4103..d610dbd 100644
--- a/gcc/testsuite/gcc.dg/compat/pr102024_test.h
+++ b/gcc/testsuite/gcc.dg/compat/pr102024_test.h
@@ -4,3 +4,9 @@ T(2,int:0;float a;,F(2,a,2.25f,16.5f))
 T(3,double a;long long:0;double b;,F(3,a,42.0,43.125)F(3,b,-17.5,35.75))
 T(4,double a;long long:0;,F(4,a,1.0,17.125))
 T(5,long long:0;double a;,F(5,a,2.25,16.5))
+T(6,float a;struct{}b;float c;,F(6,a,42.0f,43.125f)F(6,c,-17.5f,35.75f))
+T(7,float a;struct{}b[0];;,F(7,a,1.0f,17.125f))
+T(8,int a[0];float b;,F(8,b,2.25f,16.5f))
+T(9,double a;long long b[0];double c;,F(9,a,42.0,43.125)F(9,c,-17.5,35.75))
+T(10,double a;struct{}b;,F(10,a,1.0,17.125))
+T(11,struct{}a[0];double b;,F(11,b,2.25,16.5))