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Do not require memset elimination in explicit_bzero test

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Some targets fail to apply dead store elimination to the
memset call in setup_ordinary_clear.  Before this commit,
this causes the test case to fail.  Instead, the test case
now logs lack of memset elimination as an informational
message.
This commit is contained in:
Florian Weimer 2016-12-20 11:01:05 +01:00
parent 525f803984
commit 8d71242eb7
3 changed files with 29 additions and 9 deletions
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9
ChangeLog
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@ -1,3 +1,12 @@
2016-12-20 Florian Weimer <fweimer@redhat.com>
Do not require memset elimination in explicit_bzero test.
* string/tst-xbzero-opt.c (prepare_test_buffer): Force inlining.
(enum test_expectation): Add NO_EXPECTATIONS.
(subtests): NO_EXPECTATIONS for ordinary clear.
(check_test_buffer): Handle NO_EXPECTATIONS.
* string/Makefile (CFLAGS-tst-xbzero-opt.c): Compile with -O3.
2016-12-20 Joseph Myers <joseph@codesourcery.com>
* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]

1
string/Makefile
View File

@ -71,6 +71,7 @@ CFLAGS-tst-strlen.c = -fno-builtin
CFLAGS-stratcliff.c = -fno-builtin
CFLAGS-test-ffs.c = -fno-builtin
CFLAGS-tst-inlcall.c = -fno-builtin
CFLAGS-tst-xbzero-opt.c = -O3
ifeq ($(run-built-tests),yes)
$(objpfx)tst-svc-cmp.out: tst-svc.expect $(objpfx)tst-svc.out

28
string/tst-xbzero-opt.c
View File

@ -88,19 +88,19 @@ static const unsigned char test_pattern[16] =
between preparing it and letting it go out of scope, and we expect
to find it. This confirms that the test buffer does get filled in
and we can find it from the stack buffer. In the "ordinary_clear"
case, we clear it using memset, and we expect to find it. This
confirms that the compiler can optimize out block clears in this
context; if it can't, the real test might be succeeding for the
wrong reason. Finally, the "explicit_clear" case uses
explicit_bzero and expects _not_ to find the test buffer, which is
the real test. */
case, we clear it using memset. Depending on the target, the
compiler may not be able to apply dead store elimination to the
memset call, so the test does not fail if the memset is not
eliminated. Finally, the "explicit_clear" case uses explicit_bzero
and expects _not_ to find the test buffer, which is the real
test. */
static ucontext_t uc_main, uc_co;
/* Always check the test buffer immediately after filling it; this
makes externally visible side effects depend on the buffer existing
and having been filled in. */
static void
static inline __attribute__ ((always_inline)) void
prepare_test_buffer (unsigned char *buf)
{
for (unsigned int i = 0; i < PATTERN_REPS; i++)
@ -133,7 +133,10 @@ setup_explicit_clear (void)
explicit_bzero (buf, TEST_BUFFER_SIZE);
}
enum test_expectation { EXPECT_NONE, EXPECT_SOME, EXPECT_ALL };
enum test_expectation
{
EXPECT_NONE, EXPECT_SOME, EXPECT_ALL, NO_EXPECTATIONS
};
struct subtest
{
void (*setup_subtest) (void);
@ -145,7 +148,9 @@ static const struct subtest *cur_subtest;
static const struct subtest subtests[] =
{
{ setup_no_clear, "no clear", EXPECT_SOME },
{ setup_ordinary_clear, "ordinary clear", EXPECT_SOME },
/* The memset may happen or not, depending on compiler
optimizations. */
{ setup_ordinary_clear, "ordinary clear", NO_EXPECTATIONS },
{ setup_explicit_clear, "explicit clear", EXPECT_NONE },
{ 0, 0, -1 }
};
@ -225,6 +230,11 @@ check_test_buffer (enum test_expectation expected,
}
break;
case NO_EXPECTATIONS:
printf ("INFO: %s/%s: found %d patterns%s\n", label, stage, cnt,
cnt == 0 ? " (memset not eliminated)" : "");
break;
default:
printf ("ERROR: %s/%s: invalid value for 'expected' = %d\n",
label, stage, (int)expected);