On October 25, 2016 5:03:15 PM GMT+02:00, Michael Matz <m...@suse.de> wrote:
>Hi,
>
>these are ICEs by the loop splitting pass. Two problems: using
>inconsistent types for operations and not dealing correctly with
>certain
>loop forms.
>
>First (78060 and 78088): I initially used an ideosyncratic way of
>calculating the new loop bound, needing several type switches that I
>haven't implemented correctly. Reordering the order of evaluations
>makes
>this easier and fixes the ICEs.
>
>Second (78061): I need to know the exit values of all loop phis. In
>simple loop forms (where the single exit is after the loop body) that's
>
>easy: it's the same as the value on the backedge. If the exit is in
>the
>middle of a loop that's not the case. This mattered only for virtual
>ops.
>All other values already needed a loop-closed phi-node before or in the
>
>latch block, which made it not empty which rejected the loop form.
>I've
>added a predicate that explicitely checks that the exit values are
>easily
>computable (i.e. that the back edge value is indeed also the exit
>value).
>
>Together regstrapped on x86-64, all languages + ada. Okay for trunk?
OK.
Thanks,
Richard.
>
>Ciao,
>Michael.
>
> PR tree-optimization/78060
> PR tree-optimization/78061
> PR tree-optimization/78088
> * tree-ssa-loop-split.c (easy_exit_values): New function.
> (tree_ssa_split_loops): Use it.
> (compute_new_first_bound): Change order of operations,
> fix invalid use of types.
>
>testsuite:
> * g++.dg/pr78060.C: New test.
> * gfortran.dg/pr78061.f: New test.
> * g++.dg/pr78088.C: New test.
>
>commit 10cbbd81f96d5183979dae647b77ee804179780e
>Author: Michael Matz <m...@suse.de>
>Date: Mon Oct 24 17:14:08 2016 +0200
>
> pr78060 pr78061 pr78088
>
>diff --git a/gcc/testsuite/g++.dg/pr78060.C
>b/gcc/testsuite/g++.dg/pr78060.C
>new file mode 100644
>index 0000000..d6cc7b3
>--- /dev/null
>+++ b/gcc/testsuite/g++.dg/pr78060.C
>@@ -0,0 +1,14 @@
>+// PR tree-optimization/78060
>+// { dg-do compile }
>+// { dg-options "-O3 -fsplit-loops" }
>+class A {
>+public:
>+ template <typename T2> int &operator[](T2);
>+};
>+int a;
>+A b;
>+void fn1() {
>+ long c;
>+ for (int l; l < c; ++l)
>+ b[l] = l < 2 ?: a;
>+}
>diff --git a/gcc/testsuite/g++.dg/pr78088.C
>b/gcc/testsuite/g++.dg/pr78088.C
>new file mode 100644
>index 0000000..1a5c063
>--- /dev/null
>+++ b/gcc/testsuite/g++.dg/pr78088.C
>@@ -0,0 +1,19 @@
>+// PR tree-optimization/78088
>+// { dg-do compile }
>+// { dg-options "-O3 -fsplit-loops" }
>+class A {
>+public:
>+ int m_fn1();
>+};
>+struct B : A {
>+ void m_fn2();
>+};
>+void B::m_fn2() {
>+ long a;
>+ int b, c;
>+ for (;;) {
>+ c = 0;
>+ for (; c < a; ++c, ++b)
>+ b > 0 ? m_fn1() : 0;
>+ }
>+}
>diff --git a/gcc/testsuite/gfortran.dg/pr78061.f
>b/gcc/testsuite/gfortran.dg/pr78061.f
>new file mode 100644
>index 0000000..7e4dd3d
>--- /dev/null
>+++ b/gcc/testsuite/gfortran.dg/pr78061.f
>@@ -0,0 +1,18 @@
>+! { dg-do compile }
>+! { dg-options "-O3 -fsplit-loops" }
>+ SUBROUTINE SSYMM(C)
>+ REAL C(LDC,*)
>+ LOGICAL LSAME
>+ LOGICAL UPPER
>+ IF (LSAME) THEN
>+ DO 170 J = 1,N
>+ DO 140 K = 1,J
>+ IF (UPPER) THEN
>+ END IF
>+ 140 CONTINUE
>+ DO 160 K = J + 1,N
>+ C(I,J) = B(K)
>+ 160 CONTINUE
>+ 170 CONTINUE
>+ END IF
>+ END
>diff --git a/gcc/tree-ssa-loop-split.c b/gcc/tree-ssa-loop-split.c
>index 53abb36..dac68e6 100644
>--- a/gcc/tree-ssa-loop-split.c
>+++ b/gcc/tree-ssa-loop-split.c
>@@ -190,13 +190,40 @@ find_or_create_guard_phi (struct loop *loop, tree
>guard_iv, affine_iv * /*iv*/)
> return NULL;
> }
>
>+/* Returns true if the exit values of all loop phi nodes can be
>+ determined easily (i.e. that connect_loop_phis can determine them).
> */
>+
>+static bool
>+easy_exit_values (struct loop *loop)
>+{
>+ edge exit = single_exit (loop);
>+ edge latch = loop_latch_edge (loop);
>+ gphi_iterator psi;
>+
>+ /* Currently we regard the exit values as easy if they are the same
>+ as the value over the backedge. Which is the case if the
>definition
>+ of the backedge value dominates the exit edge. */
>+ for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next
>(&psi))
>+ {
>+ gphi *phi = psi.phi ();
>+ tree next = PHI_ARG_DEF_FROM_EDGE (phi, latch);
>+ basic_block bb;
>+ if (TREE_CODE (next) == SSA_NAME
>+ && (bb = gimple_bb (SSA_NAME_DEF_STMT (next)))
>+ && !dominated_by_p (CDI_DOMINATORS, exit->src, bb))
>+ return false;
>+ }
>+
>+ return true;
>+}
>+
> /* This function updates the SSA form after connect_loops made a new
> edge NEW_E leading from LOOP1 exit to LOOP2 (via in intermediate
> conditional). I.e. the second loop can now be entered either
> via the original entry or via NEW_E, so the entry values of LOOP2
> phi nodes are either the original ones or those at the exit
> of LOOP1. Insert new phi nodes in LOOP2 pre-header reflecting
>- this. */
>+ this. The loops need to fulfill easy_exit_values(). */
>
> static void
> connect_loop_phis (struct loop *loop1, struct loop *loop2, edge new_e)
>@@ -383,37 +410,37 @@ compute_new_first_bound (gimple_seq *stmts,
>struct tree_niter_desc *niter,
> TREE_TYPE (controlbase),
> controlbase, controlstep);
>
>- /* Compute beg-guard_init. */
>+ /* Compute end-beg. */
>+ gimple_seq stmts2;
>+ tree end = force_gimple_operand (niter->bound, &stmts2,
>+ true, NULL_TREE);
>+ gimple_seq_add_seq_without_update (stmts, stmts2);
> if (POINTER_TYPE_P (TREE_TYPE (enddiff)))
> {
>- tree tem = gimple_convert (stmts, sizetype, guard_init);
>+ tree tem = gimple_convert (stmts, sizetype, enddiff);
> tem = gimple_build (stmts, NEGATE_EXPR, sizetype, tem);
> enddiff = gimple_build (stmts, POINTER_PLUS_EXPR,
> TREE_TYPE (enddiff),
>- enddiff, tem);
>+ end, tem);
> }
> else
> enddiff = gimple_build (stmts, MINUS_EXPR, TREE_TYPE (enddiff),
>- enddiff, guard_init);
>+ end, enddiff);
>
>- /* Compute end-(beg-guard_init). */
>- gimple_seq stmts2;
>- tree newbound = force_gimple_operand (niter->bound, &stmts2,
>- true, NULL_TREE);
>- gimple_seq_add_seq_without_update (stmts, stmts2);
>-
>- if (POINTER_TYPE_P (TREE_TYPE (enddiff))
>- || POINTER_TYPE_P (TREE_TYPE (newbound)))
>+ /* Compute guard_init + (end-beg). */
>+ tree newbound;
>+ enddiff = gimple_convert (stmts, TREE_TYPE (guard_init), enddiff);
>+ if (POINTER_TYPE_P (TREE_TYPE (guard_init)))
> {
> enddiff = gimple_convert (stmts, sizetype, enddiff);
> enddiff = gimple_build (stmts, NEGATE_EXPR, sizetype, enddiff);
> newbound = gimple_build (stmts, POINTER_PLUS_EXPR,
>- TREE_TYPE (newbound),
>- newbound, enddiff);
>+ TREE_TYPE (guard_init),
>+ guard_init, enddiff);
> }
> else
>- newbound = gimple_build (stmts, MINUS_EXPR, TREE_TYPE (enddiff),
>- newbound, enddiff);
>+ newbound = gimple_build (stmts, PLUS_EXPR, TREE_TYPE (guard_init),
>+ guard_init, enddiff);
>
> /* Depending on the direction of the IVs the new bound for the first
> loop is the minimum or maximum of old bound and border.
>@@ -449,7 +476,6 @@ compute_new_first_bound (gimple_seq *stmts, struct
>tree_niter_desc *niter,
> build_int_cst (type2, addbound));
> }
>
>- newbound = gimple_convert (stmts, TREE_TYPE (border), newbound);
> tree newend = gimple_build (stmts, minmax, TREE_TYPE (border),
> border, newbound);
> return newend;
>@@ -615,6 +641,7 @@ tree_ssa_split_loops (void)
> original exit before. */
> && empty_block_p (loop->latch)
> && !optimize_loop_for_size_p (loop)
>+ && easy_exit_values (loop)
> && number_of_iterations_exit (loop, single_exit (loop), &niter,
> false, true)
> && niter.cmp != ERROR_MARK
