powerpc/SelectOp: optimize the pattern ((x >>s N) & N1) & N2 common in a certain customer's code

backend/Coloringaux: avoid spilling the dummy result registers for built-ins that have no result.


git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1799 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e

1 files changed, 7 insertions, 0 deletions

diff --git a/powerpc/SelectOp.vp b/powerpc/SelectOp.vp
index 40c9011..3bb5544 100644
--- a/powerpc/SelectOp.vp
+++ b/powerpc/SelectOp.vp
@@ -210,6 +210,13 @@ Nondetfunction andimm (n1: int) (e2: expr) :=
   match e2 with
   | Eop (Ointconst n2) Enil =>
       Eop (Ointconst (Int.and n1 n2)) Enil
+  | Eop (Oandimm n2) (Eop (Oshrimm amount) (t2:::Enil) ::: Enil) =>
+      let n := Int.and n1 n2 in
+      if Int.eq (Int.shru (Int.shl n amount) amount) n
+      && Int.ltu amount Int.iwordsize
+      then rolm t2 (Int.sub Int.iwordsize amount) 
+                   (Int.and (Int.shru Int.mone amount) n)
+      else Eop (Oandimm n) (Eop (Oshrimm amount) (t2:::Enil) ::: Enil)
   | Eop (Oandimm n2) (t2:::Enil) =>
       Eop (Oandimm (Int.and n1 n2)) (t2:::Enil)
   | Eop (Orolm amount2 mask2) (t2:::Enil) =>