[committed] Backport of PR40421 to 4.4 branch

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

The pr40421.f90 testcase below ICEs on the 4.4 branch, fixed by backporting
richi's fix.  Incidentally, that testcase stopped ICEing when predcom has
been moved in passes.c, while gamess the other testcase richi committed
started failing at that point.

Bootstrapped/regtested on x86_64-linux and i686-linux, committed to 4.4
branch.

Will commit the new testcase to 4.6/4.5 too.

2010-07-01  Jakub Jelinek  <jakub@redhat.com>

	Backport from mainline
	2009-06-13  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/40421
	* tree-predcom.c (should_unroll_loop_p): Remove.
	(tree_predictive_commoning_loop): Use can_unroll_loop_p.

	* gfortran.fortran-torture/compile/pr40421.f: New testcase.

	* gfortran.fortran-torture/compile/pr40421.f90: New test.

--- gcc/tree-predcom.c	(revision 148457)
+++ gcc/tree-predcom.c	(revision 148458)
@@ -1870,43 +1870,6 @@ execute_pred_commoning_cbck (struct loop
   execute_pred_commoning (loop, dta->chains, dta->tmp_vars);
 }
 
-/* Returns true if we can and should unroll LOOP FACTOR times.  Number
-   of iterations of the loop is returned in NITER.  */
-
-static bool
-should_unroll_loop_p (struct loop *loop, unsigned factor,
-		      struct tree_niter_desc *niter)
-{
-  edge exit;
-
-  if (factor == 1)
-    return false;
-
-  /* Check whether unrolling is possible.  We only want to unroll loops
-     for that we are able to determine number of iterations.  We also
-     want to split the extra iterations of the loop from its end,
-     therefore we require that the loop has precisely one
-     exit.  */
-
-  exit = single_dom_exit (loop);
-  if (!exit)
-    return false;
-
-  if (!number_of_iterations_exit (loop, exit, niter, false))
-    return false;
-
-  /* And of course, we must be able to duplicate the loop.  */
-  if (!can_duplicate_loop_p (loop))
-    return false;
-
-  /* The final loop should be small enough.  */
-  if (tree_num_loop_insns (loop, &eni_size_weights) * factor
-      > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS))
-    return false;
-
-  return true;
-}
-
 /* Base NAME and all the names in the chain of phi nodes that use it
    on variable VAR.  The phi nodes are recognized by being in the copies of
    the header of the LOOP.  */
@@ -2544,7 +2507,8 @@ tree_predictive_commoning_loop (struct l
      that its number of iterations is divisible by the factor.  */
   unroll_factor = determine_unroll_factor (chains);
   scev_reset ();
-  unroll = should_unroll_loop_p (loop, unroll_factor, &desc);
+  unroll = (unroll_factor > 1
+	    && can_unroll_loop_p (loop, unroll_factor, &desc));
   exit = single_dom_exit (loop);
 
   /* Execute the predictive commoning transformations, and possibly unroll the
--- gcc/testsuite/gfortran.fortran-torture/compile/pr40421.f	(revision 0)
+++ gcc/testsuite/gfortran.fortran-torture/compile/pr40421.f	(revision 148458)
@@ -0,0 +1,18 @@
+      SUBROUTINE VROT2(N,DIS)
+      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
+      PARAMETER(ZERO=0.0D+00)
+      COMMON /SYMSPD/ PTR(3,144)
+      DIMENSION DIS(3,2),TMP(3,2)
+      DO I = 1,3
+        TMP1 = ZERO
+        DO J = 1,3
+          TMP1 = TMP1 + PTR(I,N+J)
+        END DO
+        TMP(I,1) = TMP1
+      END DO
+      DO I = 1,3
+        DIS(I,1) = TMP(I,1)
+      END DO
+      RETURN
+      END
+
--- gcc/testsuite/gfortran.fortran-torture/compile/pr40421.f90.jj	2010-07-01 12:22:03.000000000 +0200
+++ gcc/testsuite/gfortran.fortran-torture/compile/pr40421.f90	2010-07-01 12:21:29.000000000 +0200
@@ -0,0 +1,15 @@
+subroutine pr40421 (j, q, r)
+  double precision :: q(1,1), r(1,1,3)
+  save
+  integer :: i, j, m, n
+  double precision :: s, t, u
+  do i=1,2
+    do m=1,j
+      do n=1,1
+        s=q(n,m)*r(n,m,1)
+        t=q(n,m)*r(n,m,2)
+        u=q(n,m)*r(n,m,3)
+      end do
+    end do
+  end do
+end

	Jakub