ash: gc problem.

On 32 bit x86 Solaris 10, with gcc 4.9.0, this issue caused a
miscompilation of the pset macro, due to ash abruptly
returning zero, causing the op-code field of an instruction to
be NOOP rather than GCALL.

I'm committing this fix just for reference; I will immediately
replace it with a refactoring of the function.

* arith.c (ash): Add a gc_hint to prevent the a bignum from
being reclaimed if the b = make_bignum() triggers gc.
This happens in the case when the previous case computes
a = make_bignum() and falls through.

1 files changed, 1 insertions, 0 deletions

diff --git a/arith.c b/arith.c
index fdb294b7..f374ddf4 100644
--- a/arith.c
+++ b/arith.c
@@ -3235,6 +3235,7 @@ val ash(val a, val bits)
       b = make_bignum();
       if ((mpe = mp_shift(mp(a), mp(b), bn)) != MP_OKAY)
         break;
+      gc_hint(a);
       return normalize(b);
     default:
       goto bad3;