This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [lno] [RFC] if-conversion and auto vectorizer


On Mar 15, 2004, at 7:33 PM, Richard Henderson wrote:

One thing that might should be checked before marking various
variables for ssa-renaming, however, is that you get

	if (x_1 < y_1)
	  x_2 = a, y_2 = b;
	x_3 = PHI(x_1, x_2)
	y_3 = PHI(y_1, y_2)
 ==>
	x_3 = (x_1 < y_1 ? a : x_1)
	y_3 = (x_1 < y_1 ? b : y_1)

Note that x_1 outlives the creation of x_3, which is new to
this transformed code.  This mere fact might argue for the
creation of a boolean temporary for the comparison.

Yes. I also need to simplify boolean exp.

--
Devang

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]