From: Jakub Jelinek <jakub@redhat.com>
To: Jeff Law <law@redhat.com>
Cc: gcc-patches@gcc.gnu.org
Subject: [PATCH] Improve VEC_BASE
Date: Mon, 07 Nov 2011 21:34:00 -0000 [thread overview]
Message-ID: <20111107212547.GO27375@tyan-ft48-01.lab.bos.redhat.com> (raw)
Hi!
This patch attempts to optimize VEC_BASE if we know
that offsetof of base is 0 (unless the compiler is doing something
strange, it is true).
It doesn't have a clear code size effect, some .text sections
grew, supposedly because of more inlining, some .text sections shrunk.
Bootstrapped/regtested on x86_64-linux and i686-linux.
2011-11-07 Jakub Jelinek <jakub@redhat.com>
* vec.h (VEC_BASE): If base is at offset 0 in the structure,
use &(P)->base even if P is NULL.
--- gcc/vec.h.jj 2011-09-08 11:21:10.000000000 +0200
+++ gcc/vec.h 2011-11-07 18:45:33.000000000 +0100
@@ -549,7 +549,12 @@ typedef struct VEC(T,A) \
} VEC(T,A)
/* Convert to base type. */
+#if GCC_VERSION >= 4000
+#define VEC_BASE(P) \
+ ((offsetof (__typeof (*P), base) == 0 || (P)) ? &(P)->base : 0)
+#else
#define VEC_BASE(P) ((P) ? &(P)->base : 0)
+#endif
/* Vector of integer-like object. */
#define DEF_VEC_I(T) \
Jakub
next reply other threads:[~2011-11-07 21:26 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-07 21:34 Jakub Jelinek [this message]
2011-11-07 23:25 ` Richard Guenther
2011-11-08 0:34 ` Jeff Law
2011-11-08 10:12 ` Richard Guenther
2011-11-08 10:29 ` Richard Guenther
2011-11-08 19:35 ` Jeff Law
2011-11-08 19:54 ` Jeff Law
2011-11-09 9:42 ` Richard Guenther
2011-11-11 8:27 ` Jeff Law
2011-11-11 9:42 ` Jakub Jelinek
2011-11-11 20:21 ` Jeff Law
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