This fixes PR58697 by instead of trying to preserve reference structure
when generating initial loads for the predictive commoned loop, just
builds an approprate MEM_REF. That now can handle the cases that
previously could be discovered as non-trapping (all constant offsets).
I don't see a better way avoiding the out-of-bounds array access
it currently generates (with preserving the transformation and not
regressing other testcases).
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
Richard.
2013-11-06 Richard Biener <rguent...@suse.de>
PR tree-optimization/58653
* tree-predcom.c (ref_at_iteration): Rewrite to generate
a MEM_REF.
(prepare_initializers_chain): Adjust.
* gcc.dg/tree-ssa/predcom-6.c: New testcase.
* gcc.dg/tree-ssa/predcom-7.c: Likewise.
Index: gcc/tree-predcom.c
===================================================================
*** gcc/tree-predcom.c (revision 204396)
--- gcc/tree-predcom.c (working copy)
*************** replace_ref_with (gimple stmt, tree new_
*** 1323,1412 ****
gsi_insert_after (&bsi, new_stmt, GSI_NEW_STMT);
}
! /* Returns the reference to the address of REF in the ITER-th iteration of
! LOOP, or NULL if we fail to determine it (ITER may be negative). We
! try to preserve the original shape of the reference (not rewrite it
! as an indirect ref to the address), to make tree_could_trap_p in
! prepare_initializers_chain return false more often. */
! static tree
! ref_at_iteration (struct loop *loop, tree ref, int iter)
{
! tree idx, *idx_p, type, val, op0 = NULL_TREE, ret;
! affine_iv iv;
! bool ok;
!
! if (handled_component_p (ref))
! {
! op0 = ref_at_iteration (loop, TREE_OPERAND (ref, 0), iter);
! if (!op0)
! return NULL_TREE;
! }
! else if (!INDIRECT_REF_P (ref)
! && TREE_CODE (ref) != MEM_REF)
! return unshare_expr (ref);
!
! if (TREE_CODE (ref) == MEM_REF)
! {
! ret = unshare_expr (ref);
! idx = TREE_OPERAND (ref, 0);
! idx_p = &TREE_OPERAND (ret, 0);
! }
! else if (TREE_CODE (ref) == COMPONENT_REF)
! {
! /* Check that the offset is loop invariant. */
! if (TREE_OPERAND (ref, 2)
! && !expr_invariant_in_loop_p (loop, TREE_OPERAND (ref, 2)))
! return NULL_TREE;
!
! return build3 (COMPONENT_REF, TREE_TYPE (ref), op0,
! unshare_expr (TREE_OPERAND (ref, 1)),
! unshare_expr (TREE_OPERAND (ref, 2)));
! }
! else if (TREE_CODE (ref) == ARRAY_REF)
! {
! /* Check that the lower bound and the step are loop invariant. */
! if (TREE_OPERAND (ref, 2)
! && !expr_invariant_in_loop_p (loop, TREE_OPERAND (ref, 2)))
! return NULL_TREE;
! if (TREE_OPERAND (ref, 3)
! && !expr_invariant_in_loop_p (loop, TREE_OPERAND (ref, 3)))
! return NULL_TREE;
!
! ret = build4 (ARRAY_REF, TREE_TYPE (ref), op0, NULL_TREE,
! unshare_expr (TREE_OPERAND (ref, 2)),
! unshare_expr (TREE_OPERAND (ref, 3)));
! idx = TREE_OPERAND (ref, 1);
! idx_p = &TREE_OPERAND (ret, 1);
! }
! else
! return NULL_TREE;
!
! ok = simple_iv (loop, loop, idx, &iv, true);
! if (!ok)
! return NULL_TREE;
! iv.base = expand_simple_operations (iv.base);
! if (integer_zerop (iv.step))
! *idx_p = unshare_expr (iv.base);
else
! {
! type = TREE_TYPE (iv.base);
! if (POINTER_TYPE_P (type))
! {
! val = fold_build2 (MULT_EXPR, sizetype, iv.step,
! size_int (iter));
! val = fold_build_pointer_plus (iv.base, val);
! }
! else
! {
! val = fold_build2 (MULT_EXPR, type, iv.step,
! build_int_cst_type (type, iter));
! val = fold_build2 (PLUS_EXPR, type, iv.base, val);
! }
! *idx_p = unshare_expr (val);
! }
!
! return ret;
}
/* Get the initialization expression for the INDEX-th temporary variable
--- 1323,1351 ----
gsi_insert_after (&bsi, new_stmt, GSI_NEW_STMT);
}
! /* Returns a memory reference to DR in the ITER-th iteration of
! the loop it was analyzed in. Append init stmts to STMTS. */
! static tree
! ref_at_iteration (data_reference_p dr, int iter, gimple_seq *stmts)
{
! tree off = DR_OFFSET (dr);
! tree coff = DR_INIT (dr);
! if (iter == 0)
! ;
! else if (TREE_CODE (DR_STEP (dr)) == INTEGER_CST)
! coff = size_binop (PLUS_EXPR, coff,
! size_binop (MULT_EXPR, DR_STEP (dr), ssize_int (iter)));
else
! off = size_binop (PLUS_EXPR, off,
! size_binop (MULT_EXPR, DR_STEP (dr), ssize_int (iter)));
! tree addr = fold_build_pointer_plus (DR_BASE_ADDRESS (dr), off);
! addr = force_gimple_operand_1 (addr, stmts, is_gimple_mem_ref_addr,
! NULL_TREE);
! return fold_build2 (MEM_REF, TREE_TYPE (DR_REF (dr)),
! addr,
! fold_convert (reference_alias_ptr_type (DR_REF (dr)),
! coff));
}
/* Get the initialization expression for the INDEX-th temporary variable
*************** prepare_initializers_chain (struct loop
*** 2365,2378 ****
if (chain->inits[i] != NULL_TREE)
continue;
! init = ref_at_iteration (loop, DR_REF (dr), (int) i - n);
! if (!init)
! return false;
!
if (!chain->all_always_accessed && tree_could_trap_p (init))
return false;
- init = force_gimple_operand (init, &stmts, false, NULL_TREE);
if (stmts)
gsi_insert_seq_on_edge_immediate (entry, stmts);
--- 2304,2313 ----
if (chain->inits[i] != NULL_TREE)
continue;
! init = ref_at_iteration (dr, (int) i - n, &stmts);
if (!chain->all_always_accessed && tree_could_trap_p (init))
return false;
if (stmts)
gsi_insert_seq_on_edge_immediate (entry, stmts);
Index: gcc/testsuite/gcc.dg/tree-ssa/predcom-6.c
===================================================================
*** gcc/testsuite/gcc.dg/tree-ssa/predcom-6.c (revision 0)
--- gcc/testsuite/gcc.dg/tree-ssa/predcom-6.c (working copy)
***************
*** 0 ****
--- 1,17 ----
+ /* { dg-do run } */
+ /* { dg-options "-O3 -fdump-tree-pcom-details" } */
+
+ int a, c, e[5][2];
+ unsigned int d;
+
+ int
+ main ()
+ {
+ for (d = 0; d < 2; d++)
+ if (a ? 0 : e[c + 3][d] & e[c + 4][d])
+ break;
+ return 0;
+ }
+
+ /* { dg-final { scan-tree-dump "Executing predictive commoning" "pcom" } } */
+ /* { dg-final { cleanup-tree-dump "pcom" } } */
Index: gcc/testsuite/gcc.dg/tree-ssa/predcom-7.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/predcom-7.c (revision 0)
+++ gcc/testsuite/gcc.dg/tree-ssa/predcom-7.c (working copy)
@@ -0,0 +1,18 @@
+/* { dg-do run } */
+/* { dg-options "-O3 -fdump-tree-pcom-details" } */
+
+int b, f, d[5][2];
+unsigned int c;
+
+int
+main ()
+{
+ for (c = 0; c < 2; c++)
+ if (d[b + 3][c] & d[b + 4][c])
+ if (f)
+ break;
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump "Executing predictive commoning" "pcom" } } */
+/* { dg-final { cleanup-tree-dump "pcom" } } */
