From 0659ad44847d4a3afd278b73fffec213a3f6e366 Mon Sep 17 00:00:00 2001
From: Alex Shinn <ashinn@users.noreply.github.com>
Date: Sun, 14 Apr 2013 05:01:38 +0000
Subject: [PATCH] Need to GC preserve earlier in sexp_sqrt.

---
 eval.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/eval.c b/eval.c
index 8973d5cd..b9dc37b8 100644
--- a/eval.c
+++ b/eval.c
@@ -1398,6 +1398,7 @@ sexp sexp_sqrt (sexp ctx, sexp self, sexp_sint_t n, sexp z) {
 #endif
   double d, r;
   sexp_gc_var1(res);
+  sexp_gc_preserve1(ctx, res);
 #if SEXP_USE_BIGNUMS
   if (sexp_bignump(z)) {
     negativep = sexp_bignum_sign(z) < 0;
@@ -1410,9 +1411,10 @@ sexp sexp_sqrt (sexp ctx, sexp self, sexp_sint_t n, sexp z) {
     d = (double)sexp_unbox_fixnum(z);
   maybe_convert_ratio(z)        /* XXXX add ratio sqrt */
   maybe_convert_complex(z, sexp_complex_sqrt)
-  else
+  else {
+    sexp_gc_release1(ctx);
     return sexp_type_exception(ctx, self, SEXP_NUMBER, z);
-  sexp_gc_preserve1(ctx, res);
+  }
 #if SEXP_USE_COMPLEX
   if (d < 0) {
     negativep = 1;