[PATCH v2] rtl: fix build failure on -fchecking=2 [PR111642]

[Sergei Trofimovich]

From: Sergei Trofimovich <siarh...@google.com>

Before the change `make bootstrap4` (or `make profiledbootstrap`) failed
as:

    gcc/rtl-tests.cc:249:25:   in ‘constexpr’ expansion of ‘poly_int<1, long 
int>(1, 1)’
    gcc/poly-int.h:453:5: error: too many initializers for ‘long int [1]’

The failure happened only in stage4 due to a gcc bug which accepts
invalid C++ without `-fchecking=2`: https://gcc.gnu.org/PR111647#c1.

The change hides tests that rely on 2 and more polynomials under `#if`.

gcc/
        PR bootstrap/111642
        * rtl-tests.cc (const_poly_int_tests): Guard tests with
        NUM_POLY_INT_COEFFS > 1.
        * simplify-rtx.cc (simplify_const_poly_int_tests): Ditto.
---
 gcc/rtl-tests.cc    | 23 +++++++----------------
 gcc/simplify-rtx.cc | 21 ++++++---------------
 2 files changed, 13 insertions(+), 31 deletions(-)

diff --git a/gcc/rtl-tests.cc b/gcc/rtl-tests.cc
index ae8669419b6..d4130572501 100644
--- a/gcc/rtl-tests.cc
+++ b/gcc/rtl-tests.cc
@@ -228,24 +228,14 @@ test_uncond_jump ()
                      jump_insn);
 }
 
-template<unsigned int N>
-struct const_poly_int_tests
-{
-  static void run ();
-};
-
-template<>
-struct const_poly_int_tests<1>
-{
-  static void run () {}
-};
-
 /* Test various CONST_POLY_INT properties.  */
 
-template<unsigned int N>
-void
-const_poly_int_tests<N>::run ()
+static void
+const_poly_int_tests ()
 {
+  /* `poly_int64` call with two parameters requires target with at
+   least 2 COEFFs.  */
+#if NUM_POLY_INT_COEFFS > 1
   rtx x1 = gen_int_mode (poly_int64 (1, 1), QImode);
   rtx x255 = gen_int_mode (poly_int64 (1, 255), QImode);
 
@@ -282,6 +272,7 @@ const_poly_int_tests<N>::run ()
             gen_int_mode (poly_int64 (5, -2), QImode));
   ASSERT_EQ (plus_constant (QImode, x1, poly_int64 (4, -2)),
             gen_int_mode (poly_int64 (5, -1), QImode));
+#endif
 }
 
 /* Check dumping of repeated RTL vectors.  */
@@ -317,7 +308,7 @@ rtl_tests_cc_tests ()
   test_dumping_rtx_reuse ();
   test_single_set ();
   test_uncond_jump ();
-  const_poly_int_tests<NUM_POLY_INT_COEFFS>::run ();
+  const_poly_int_tests ();
   test_dumping_repeat ();
 
   /* Purge state.  */
diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 170406aa28b..39361b11b1a 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -8671,24 +8671,14 @@ test_vector_ops ()
     }
 }
 
-template<unsigned int N>
-struct simplify_const_poly_int_tests
-{
-  static void run ();
-};
-
-template<>
-struct simplify_const_poly_int_tests<1>
-{
-  static void run () {}
-};
-
 /* Test various CONST_POLY_INT properties.  */
 
-template<unsigned int N>
 void
-simplify_const_poly_int_tests<N>::run ()
+simplify_const_poly_int_tests ()
 {
+  /* `poly_int64` call with two parameters requires target with at
+   least 2 COEFFs.  */
+#if NUM_POLY_INT_COEFFS > 1
   rtx x1 = gen_int_mode (poly_int64 (1, 1), QImode);
   rtx x2 = gen_int_mode (poly_int64 (-80, 127), QImode);
   rtx x3 = gen_int_mode (poly_int64 (-79, -128), QImode);
@@ -8716,6 +8706,7 @@ simplify_const_poly_int_tests<N>::run ()
   ASSERT_EQ (simplify_binary_operation (IOR, QImode, x4, two), x7);
   ASSERT_EQ (simplify_subreg (HImode, x5, QImode, 0), x8);
   ASSERT_EQ (simplify_subreg (QImode, x8, HImode, offset), x5);
+#endif
 }
 
 /* Run all of the selftests within this file.  */
@@ -8725,7 +8716,7 @@ simplify_rtx_cc_tests ()
 {
   test_scalar_ops ();
   test_vector_ops ();
-  simplify_const_poly_int_tests<NUM_POLY_INT_COEFFS>::run ();
+  simplify_const_poly_int_tests ();
 }
 
 } // namespace selftest
-- 
2.42.0