[PATCH] testsuite: Remove reliance on argc in lto/pr101868_0.c

[Dimitar Dimitrov]

Some embedded targets do not pass any argv arguments.  When argc is
zero, this causes spurious failures for lto/pr101868_0.c.  Fix by
following the strategy in r0-114701-g2c49569ecea56d.  Use a volatile
variable instead of argc to inject a runtime value into the test.

I validated the following:
  - No changes in testresults for x86_64-pc-linux-gnu.
  - The spurious failures are fixed for PRU target.
  - lto/pr101868_0.c still fails on x86_64-pc-linux-gnu, if
    the PR/101868 fix (r12-2254-gfedcf3c476aff7) is reverted.

Ok for trunk?

        PR tree-optimization/101868

gcc/testsuite/ChangeLog:

        * gcc.dg/lto/pr101868_0.c (zero): New volatile variable.
        (main): Use it instead of argc.

Signed-off-by: Dimitar Dimitrov <dimi...@dinux.eu>
---
 gcc/testsuite/gcc.dg/lto/pr101868_0.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/lto/pr101868_0.c 
b/gcc/testsuite/gcc.dg/lto/pr101868_0.c
index c84d19b0267..03124308267 100644
--- a/gcc/testsuite/gcc.dg/lto/pr101868_0.c
+++ b/gcc/testsuite/gcc.dg/lto/pr101868_0.c
@@ -22,12 +22,13 @@ repro(VALUE dummy, VALUE hash)
 
 static VALUE (*that)(VALUE dummy, VALUE hash) = repro;
 
+volatile int zero = 0;
+
 int
 main(int argc, char **argv)
 {
-        argc--;
-        that(0, argc);
+        that(0, zero);
 
-        rb_check_type(argc, argc);
+        rb_check_type(zero, zero);
 
 }
-- 
2.36.1