md.texi: Mention that a target shouldn't implement vec_widen_(s|u)mul_even/odd pair...

2014-01-29  Bingfeng Mei  <bmei@broadcom.com>

	* doc/md.texi: Mention that a target shouldn't implement
	vec_widen_(s|u)mul_even/odd pair if it is less efficient
	than hi/lo pair.

From-SVN: r207228

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ddf35958c4ffdada49b3ef1cc205aa06b200164f..1dd3a58e158bdafe8999c6c46cc4601e227746b4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2014-01-29  Bingfeng Mei  <bmei@broadcom.com>
+
+       * doc/md.texi: Mention that a target shouldn't implement 
+       vec_widen_(s|u)mul_even/odd pair if it is less efficient
+       than hi/lo pair.
+
 2014-01-29  Jakub Jelinek  <jakub@redhat.com>
 
        PR tree-optimization/59594

diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index dddff7fedceb9bbdb3b0af1cb5115527dd42196b..746acc2bce7b6f79b40ec120c7ac91c7df97780e 100644 (file)
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -4918,7 +4918,8 @@ the output vector (operand 0).
 Signed/Unsigned widening multiplication.  The two inputs (operands 1 and 2)
 are vectors with N signed/unsigned elements of size S@.  Multiply the high/low
 or even/odd elements of the two vectors, and put the N/2 products of size 2*S
-in the output vector (operand 0).
+in the output vector (operand 0). A target shouldn't implement even/odd pattern
+pair if it is less efficient than lo/hi one.
 
 @cindex @code{vec_widen_ushiftl_hi_@var{m}} instruction pattern
 @cindex @code{vec_widen_ushiftl_lo_@var{m}} instruction pattern