[PATCH 1/2] git-compat-util: st_add4: work around gcc 4.2.x compiler crash

From: Eric Sunshine <sunshine@sunshineco.com>
Date: Mar 21, 2016, 04:35 UTC
Message-ID: <1458534958-6956-2-git-send-email-sunshine@sunshineco.com>
In-Reply-To: <1458534958-6956-1-git-send-email-sunshine@sunshineco.com>

Although changes by 5b442c4 (tree-diff: catch integer overflow in combine_diff_path allocation, 2016-02-19) are perfectly valid, they unfortunately trigger an internal compiler error in gcc 4.2.x:

    combine-diff.c: In function 'diff_tree_combined':
    combine-diff.c:1391: internal compiler error: Segmentation fault: 11

Experimentation reveals that changing st_add4()'s argument evaluation order is sufficient to sidestep this problem.

Although st_add3() does not trigger the compiler bug, for style consistency, change its argument evaluation order to match.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
---
 git-compat-util.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/git-compat-util.h b/git-compat-util.h
index c07e0c1..4743954 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -715,8 +715,8 @@ static inline size_t st_add(size_t a, size_t b)
 		    (uintmax_t)a, (uintmax_t)b);
 	return a + b;
 }
-#define st_add3(a,b,c)   st_add((a),st_add((b),(c)))
-#define st_add4(a,b,c,d) st_add((a),st_add3((b),(c),(d)))
+#define st_add3(a,b,c)   st_add(st_add((a),(b)),(c))
+#define st_add4(a,b,c,d) st_add(st_add3((a),(b),(c)),(d))
 
 static inline size_t st_mult(size_t a, size_t b)
 {

-- 
2.8.0.rc3.240.g104e649