This fixes a powerpc testsuite regression on trunk and 4.5.
The fix for PR43949 improved VRP, causing initialization loops
in two vectorization test cases (gcc.dg/vect/slp-perm-{5,6}.c)
to also be vectorized.  The scan-tree-dump-times check then sees
too many "vectorized 1 loops" messages, and fails.

Fixed by placing asm (""); markers in the initialization loops,
as suggested by Richard Guenther in the PR trail.

Tested on powerpc-linux where it eliminated the new FAILs for
gcc.dg/vect/slp-perm-{5,6}.c.  There was no change in the
testsuite results on x86_64-linux.  (x86_64 is not a vect_perm
target so the number of vectorized loops is not checked there.)

Ok for trunk and 4.5? (I don't have svn write access.)

/Mikael

gcc/testsuite/

2010-06-16  Mikael Pettersson  <mikpe@it.uu.se>

	PR testsuite/44538
	* gcc.dg/vect/slp-perm-5.c (main): Prevent
	initialization loop from being vectorized.
	* gcc.dg/vect/slp-perm-6.c (main): Likewise.

--- gcc-4.6-20100612/gcc/testsuite/gcc.dg/vect/slp-perm-5.c.~1~	2008-09-04 12:41:50.000000000 +0200
+++ gcc-4.6-20100612/gcc/testsuite/gcc.dg/vect/slp-perm-5.c	2010-06-15 22:08:10.000000000 +0200
@@ -63,6 +63,7 @@ int main (int argc, const char* argv[])
       output2[i] = 0;
       if (input[i] > 256)
         abort ();
+      __asm__ volatile ("");
     }
 
   foo (input, output, input2, output2);
--- gcc-4.6-20100612/gcc/testsuite/gcc.dg/vect/slp-perm-6.c.~1~	2008-09-04 12:41:50.000000000 +0200
+++ gcc-4.6-20100612/gcc/testsuite/gcc.dg/vect/slp-perm-6.c	2010-06-15 22:08:10.000000000 +0200
@@ -62,6 +62,7 @@ int main (int argc, const char* argv[])
       output2[i] = 0;
       if (input[i] > 256)
         abort ();
+      __asm__ volatile ("");
     }
 
   foo (input, output, input2, output2);