Adding an x86 maintainer in Cc:
On Tue, 11 Sep 2012, Marc Glisse wrote:
Hello,
any advice?
http://gcc.gnu.org/ml/gcc-patches/2012-09/msg00044.html
On Sun, 2 Sep 2012, Marc Glisse wrote:
Hello,
this patch passes bootstrap+testsuite. It is probably wrong in many ways,
but I don't know enough to do more without some advice.
The goal is to recognize that v[0]+v[1] can be computed with haddpd. With
the patch, v[0]-v[1] becomes hsubpd and v[1]+v[0] becomes haddpd. Also,
thanks to it, {v[0]-v[1], w[0]-w[1]} is now recognized as a single hsubpd.
1) Is a define_insn the right tool?
2) {v[0]-v[1], v[0]-v[1]} is not recognized as a hsubpd because
vec_duplicate doesn't match vec_concat. Do we really need to duplicate (no
pun intended) the pattern?
3) v[0]+v[1] is not recognized. Some pass changed their order, and nothing
tries the reverse order. I can see 3 ways: canonicalize the order at some
point, let combine try both orders for commutative operators or make the
patterns more flexible (I don't know how many would need changing).
4) I don't understand the set_attr part. I copied it from the haddpd
define_insn, and removed (set_attr "type" "sseadd") because it crashed the
compiler. isa and prefix make sense and they match the alternatives, but I
am not sure about "mode" (removing it still works IIRC).
2012-09-02 Marc Glisse <marc.gli...@inria.fr>
gcc/
* config/i386/sse.md (*sse3_h<plusminus_insn>v2df3_low): New.
gcc/testsuite/
* gcc.target/i386/pr54400.c: New testcase.
--
Marc Glisse
