[gcc(refs/users/aoliva/heads/testme)] [PR102706] [testsuite] -Wno-stringop-overflow vs Warray-bounds

[Alexandre Oliva <aoliva@gcc.gnu.org>]

https://gcc.gnu.org/g:db86e43e7ca1be9d5cce3aaa839fc6a3c6109972

commit db86e43e7ca1be9d5cce3aaa839fc6a3c6109972
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Sat Dec 3 04:31:20 2022 -0300

    [PR102706] [testsuite] -Wno-stringop-overflow vs Warray-bounds
    
    The bogus Wstringop-overflow warnings conditionally issued for
    Warray-bounds-48.c and -Wzero-length-array-bounds-2.c are expected
    under conditions that depend on the availability of certain vector
    patterns, but that don't take cost analysis into account, which
    leads to omitted expected warnings and to unexpected warnings.
    
    On riscv64-elf and arm-eabi/-mcpu=cortex-r5, for example, though the
    Warray-bounds-48.c condition passes, we don't issue warnings because
    we decide not to vectorize the assignments.
    
    On riscv64, for Wzero-length-array-bounds-2.c, we issue the expected
    warning in test_C_global_buf, but we also issue a warning for
    test_C_local_buf under the same conditions, that would be expected on
    other platforms but that is not issued on them.  On
    arm-eabi/-mcpu=cortex-r5, the condition passes so we'd expect the
    warning in both functions, but we don't warn on either.
    
    Instead of further extending the effective target tests, introduced to
    temporarily tolerate these expected bogus warnings, so as to capture
    the cost analyses that lead to the mismatched decisions, I'm disabling
    the undesired warnings for these two tests.
    
    
    for  gcc/testsuite/ChangeLog
    
            PR tree-optimization/102706
            * gcc.dg/Warray-bounds-48.c: Disable -Wstringop-overflow.
            * gcc.dg/Wzero-length-array-bounds-2.c: Likewise.

Diff:
---
 gcc/testsuite/gcc.dg/Warray-bounds-48.c            | 11 +++++++++--
 gcc/testsuite/gcc.dg/Wzero-length-array-bounds-2.c | 11 +++++++++--
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-48.c b/gcc/testsuite/gcc.dg/Warray-bounds-48.c
index 775b301e375..e9203140a27 100644
--- a/gcc/testsuite/gcc.dg/Warray-bounds-48.c
+++ b/gcc/testsuite/gcc.dg/Warray-bounds-48.c
@@ -4,6 +4,11 @@
    { dg-options "-O2 -Wall" }
    { dg-require-effective-target alloca } */
 
+/* pr102706: disabled warnings because the now-disabled conditions for the
+   bogus warnings to come up do not take cost analysis into account, and often
+   come up wrong.  */
+/* { dg-additional-options "-Wno-stringop-overflow" } */
+
 typedef __INT16_TYPE__ int16_t;
 typedef __INT32_TYPE__ int32_t;
 
@@ -30,7 +35,8 @@ static void nowarn_ax_extern (struct AX *p)
 
 static void warn_ax_local_buf (struct AX *p)
 {
-  p->ax[0] = 4; p->ax[1] = 5;  // { dg-warning "\\\[-Wstringop-overflow" "pr102706" { target { vect_slp_v2hi_store_align &&  { ! vect_slp_v4hi_store_unalign } } } }
+  p->ax[0] = 4; p->ax[1] = 5;  // { dg-bogus "\\\[-Wstringop-overflow" "pr102706" }
+                               //   { xfail { vect_slp_v2hi_store_align &&  { ! vect_slp_v4hi_store_unalign } } }
 
   p->ax[2] = 6;     // { dg-warning "\\\[-Warray-bounds" }
   p->ax[3] = 7;     // { dg-warning "\\\[-Warray-bounds" }
@@ -130,7 +136,8 @@ static void warn_a0_extern (struct A0 *p)
 
 static void warn_a0_local_buf (struct A0 *p)
 {
-  p->a0[0] = 4; p->a0[1] = 5;  // { dg-warning "\\\[-Wstringop-overflow" "pr102706" { target { vect_slp_v2hi_store_align && { ! vect_slp_v4hi_store_unalign } } } }
+  p->a0[0] = 4; p->a0[1] = 5;  // { dg-bogus "\\\[-Wstringop-overflow" "pr102706" }
+                               //   { xfail { vect_slp_v2hi_store_align && { ! vect_slp_v4hi_store_unalign } } }
 
   p->a0[2] = 6;     // { dg-warning "\\\[-Warray-bounds" }
   p->a0[3] = 7;     // { dg-warning "\\\[-Warray-bounds" }
diff --git a/gcc/testsuite/gcc.dg/Wzero-length-array-bounds-2.c b/gcc/testsuite/gcc.dg/Wzero-length-array-bounds-2.c
index 2ef5ccd564a..19932d05a31 100644
--- a/gcc/testsuite/gcc.dg/Wzero-length-array-bounds-2.c
+++ b/gcc/testsuite/gcc.dg/Wzero-length-array-bounds-2.c
@@ -4,6 +4,11 @@
    { dg-do compile }
    { dg-options "-O2 -Wall" } */
 
+/* pr102706: disabled warnings because the now-disabled conditions for the
+   bogus warnings to come up do not take cost analysis into account, and often
+   come up wrong.  */
+/* { dg-additional-options "-Wno-stringop-overflow" } */
+
 void sink (void*);
 
 struct A { int i; };
@@ -87,7 +92,8 @@ void test_C_global_buf (void)
   p->b1.a[ 1].i = 0;     // { dg-warning "\\\[-Wzero-length-bounds" }
   sink (p);
 
-  p->b2.a[ 0].i = 0;    // { dg-warning "\\\[-Wstringop-overflow" "pr102706" { target { vect_slp_v2si_store_align &&  { ! vect_slp_v4si_store_unalign } } } }
+  p->b2.a[ 0].i = 0;    // { dg-bogus "\\\[-Wstringop-overflow" "pr102706" }
+                        //   { xfail { vect_slp_v2si_store_align &&  { ! vect_slp_v4si_store_unalign } } }
   p->b2.a[ 1].i = 0;
   p->b2.a[ 2].i = 0;     // { dg-warning "\\\[-Warray-bounds" }
   p->b2.a[ 3].i = 0;     // { dg-warning "\\\[-Warray-bounds" }
@@ -117,7 +123,8 @@ void test_C_local_buf (void)
   p->b1.a[ 1].i = 8;     // { dg-warning "\\\[-Wzero-length-bounds" }
   sink (p);
 
-  p->b2.a[ 0].i = 9;
+  p->b2.a[ 0].i = 9;    // { dg-bogus "\\\[-Wstringop-overflow" "pr102706" }
+                        //   { xfail { vect_slp_v2si_store_align &&  { ! vect_slp_v4si_store_unalign } } }
   p->b2.a[ 1].i = 10;
   p->b2.a[ 2].i = 11;    // { dg-warning "\\\[-Warray-bounds" }
   p->b2.a[ 3].i = 12;    // { dg-warning "\\\[-Warray-bounds" }