https://gcc.gnu.org/g:98bc42f456d04d71fe9b2b55fa7c7ad415367bbc
commit r15-9898-g98bc42f456d04d71fe9b2b55fa7c7ad415367bbc
Author: Jakub Jelinek <ja...@redhat.com>
Date: Tue Jul 1 19:37:39 2025 +0200
testsuite: Fix up gcc.target/powerpc/builtin_altivec_tr_stxvr_runnable.c
test (test UB) [PR120919]
In my reading of the test and the instructions emitted by the
builtins, it invokes UB 4 times, each time overwriting one byte
after some variable (sc, then ss, then si and then sll).
If we are lucky, like at -O0 -mcpu=power10, there is just padding
there or something that doesn't make the tests fail, if unlucky
like with -O0 -mcpu=power10 -fstack-protector-strong,
&sc + 1 == &expected_sc
and so it overwrites the expected_sc variable.
The test fails when testing with
RUNTESTFLAGS="--target_board=unix/'{,-fstack-protector-strong}'"
on power10.
The following patch fixes that by using arrays of 2 elements, so that
the overwriting of 1 byte happens to the part of the same variable.
2025-07-01 Jakub Jelinek <ja...@redhat.com>
PR testsuite/120919
* gcc.target/powerpc/builtin_altivec_tr_stxvr_runnable.c (main):
Change
sc, ss, si and sll vars from scalars to arrays of 2 elements,
initialize and test just the first one though.
(cherry picked from commit f5282f7402939fdec910ef3743d38edac864eec8)
Diff:
---
.../powerpc/builtin_altivec_tr_stxvr_runnable.c | 40 +++++++++++-----------
1 file changed, 20 insertions(+), 20 deletions(-)
diff --git
a/gcc/testsuite/gcc.target/powerpc/builtin_altivec_tr_stxvr_runnable.c
b/gcc/testsuite/gcc.target/powerpc/builtin_altivec_tr_stxvr_runnable.c
index 4b9043797327..fab7a529e39c 100644
--- a/gcc/testsuite/gcc.target/powerpc/builtin_altivec_tr_stxvr_runnable.c
+++ b/gcc/testsuite/gcc.target/powerpc/builtin_altivec_tr_stxvr_runnable.c
@@ -27,10 +27,10 @@ int
main () {
int i;
signed long sl;
- signed char sc, expected_sc;
- signed short ss, expected_ss;
- signed int si, expected_si;
- signed long long int sll, expected_sll;
+ signed char sc[2], expected_sc;
+ signed short ss[2], expected_ss;
+ signed int si[2], expected_si;
+ signed long long int sll[2], expected_sll;
signed char *psc;
signed short *pss;
signed int *psi;
@@ -41,56 +41,56 @@ main () {
printf("Data to store [%d] = 0x%llx %llx\n", i, val.ull[1], val.ull[0]);
#endif
- psc = ≻
- pss = &ss;
- psi = &si;
- psll = &sll;
+ psc = &sc[0];
+ pss = &ss[0];
+ psi = &si[0];
+ psll = &sll[0];
sl = 1;
- sc = 0xA1;
+ sc[0] = 0xA1;
expected_sc = 0xA1;
__builtin_altivec_tr_stxvrbx (store_data, sl, psc);
- if (expected_sc != sc & 0xFF)
+ if (expected_sc != sc[0] & 0xFF)
#if DEBUG
printf(" ERROR: Signed char = 0x%x doesn't match expected value 0x%x\n",
- sc & 0xFF, expected_sc);
+ sc[0] & 0xFF, expected_sc);
#else
abort();
#endif
- ss = 0x52;
+ ss[0] = 0x52;
expected_ss = 0x1752;
__builtin_altivec_tr_stxvrhx (store_data, sl, pss);
- if (expected_ss != ss & 0xFFFF)
+ if (expected_ss != ss[0] & 0xFFFF)
#if DEBUG
printf(" ERROR: Signed short = 0x%x doesn't match expected value 0x%x\n",
- ss, expected_ss) & 0xFFFF;
+ ss[0], expected_ss) & 0xFFFF;
#else
abort();
#endif
- si = 0x21;
+ si[0] = 0x21;
expected_si = 0x54321721;
__builtin_altivec_tr_stxvrwx (store_data, sl, psi);
- if (expected_si != si)
+ if (expected_si != si[0])
#if DEBUG
printf(" ERROR: Signed int = 0x%x doesn't match expected value 0x%x\n",
- si, expected_si);
+ si[0], expected_si);
#else
abort();
#endif
- sll = 0x12FFULL;
+ sll[0] = 0x12FFULL;
expected_sll = 0xdcba9876543217FF;
__builtin_altivec_tr_stxvrdx (store_data, sl, psll);
- if (expected_sll != sll)
+ if (expected_sll != sll[0])
#if DEBUG
printf(" ERROR: Signed long long int = 0x%llx doesn't match expected value
0x%llx\n",
- sll, expected_sll);
+ sll[0], expected_sll);
#else
abort();
#endif
