Mailing List Archive

commit 7e5213f9f7a35c664bf7486e6310794f74d9e6ea
Author: Nils Goroll <nils.goroll@uplex.de>
Date: Wed Nov 10 10:53:46 2021 +0100

vmin/vmax: Avoid typeof() where we can

Reviewing flexelint output for the recently added vmin/vmax macros
made apparent that vmin_t/vmax_t basically used typeof((cast)var),
which makes for an unnecessary de-tour via typeof.

We change the min/max macros to explicitly pass the type for the
temporary variables such that typeof() is only needed for vmin/vmax.

Being at it, we also reduce the min/max case to just one take macro
("take the min/max of ...") as they only differed in a single
character, the operator.

diff --git a/include/vdef.h b/include/vdef.h
index a810be196..9b1043669 100644
--- a/include/vdef.h
+++ b/include/vdef.h
@@ -182,29 +182,24 @@ int __llvm_gcov_flush(void);

/* ref: https://gcc.gnu.org/onlinedocs/gcc/Typeof.html */

-#define _vmin(a, b, _va, _vb) \
-({ \
- typeof (a) _va = (a); \
- typeof (b) _vb = (b); \
+#define _vtake(op, ta, tb, a, b, _va, _vb) \
+ ({ \
+ ta _va = (a); \
+ tb _vb = (b); \
(void)(&_va == &_vb); \
- _va < _vb ? _va : _vb; \
+ _va op _vb ? _va : _vb; \
})

-#define _vmax(a, b, _va, _vb) \
-({ \
- typeof (a) _va = (a); \
- typeof (b) _vb = (b); \
- (void)(&_va == &_vb); \
- _va > _vb ? _va : _vb; \
-})
+#define opmin <
+#define opmax >
+#define vtake(n, ta, tb, a, b) _vtake(op ## n, ta, tb, a, b, \
+ VUNIQ_NAME(_v ## n ## A), VUNIQ_NAME(_v ## n ## B))

-#define vmin(a, b) _vmin((a), (b), VUNIQ_NAME(_vmina), \
- VUNIQ_NAME(_vminb))
-#define vmax(a, b) _vmax((a), (b), VUNIQ_NAME(_vmaxa), \
- VUNIQ_NAME(_vmaxb))
+#define vmin(a, b) vtake(min, typeof(a), typeof(b), a, b)
+#define vmax(a, b) vtake(max, typeof(a), typeof(b), a, b)

-#define vmin_t(type, a, b) vmin((type)(a), (type)(b))
-#define vmax_t(type, a, b) vmax((type)(a), (type)(b))
+#define vmin_t(type, a, b) vtake(min, type, type, a, b)
+#define vmax_t(type, a, b) vtake(max, type, type, a, b)

/**********************************************************************
* Clamp the value between two limits.
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