From 86502ecfe41ae0ba0b3698be199797496e77c8c1 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Mon, 4 Dec 2017 14:04:36 +0000 Subject: [PATCH] re PR tree-optimization/83255 ([graphite] Wrong code w/ -O1 -floop-nest-optimize) 2017-12-04 Richard Biener PR tree-optimization/83255 * graphite-isl-ast-to-gimple.c (translate_isl_ast_node_for): Re-add zero-iteration check. * gcc.dg/graphite/pr83255.c: New testcase. From-SVN: r255382 --- gcc/ChangeLog | 6 ++++++ gcc/graphite-isl-ast-to-gimple.c | 26 ++++++++++++++++++++++++++ gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.dg/graphite/pr83255.c | 28 ++++++++++++++++++++++++++++ 4 files changed, 65 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/graphite/pr83255.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 3b0f55f..c73452a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2017-12-04 Richard Biener + + PR tree-optimization/83255 + * graphite-isl-ast-to-gimple.c (translate_isl_ast_node_for): + Re-add zero-iteration check. + 2017-12-04 Segher Boessenkool PR rtl-optimization/83245 diff --git a/gcc/graphite-isl-ast-to-gimple.c b/gcc/graphite-isl-ast-to-gimple.c index 16570e1..c565cf0 100644 --- a/gcc/graphite-isl-ast-to-gimple.c +++ b/gcc/graphite-isl-ast-to-gimple.c @@ -720,6 +720,32 @@ translate_isl_ast_node_for (loop_p context_loop, __isl_keep isl_ast_node *node, ub = integer_zero_node; edge last_e = single_succ_edge (split_edge (next_e)); + + /* Compensate for the fact that we emit a do { } while loop from + a for ISL AST. + ??? We often miss constraints on niter because the SESE region + doesn't cover loop header copies. Ideally we'd add constraints + for all relevant dominating conditions. */ + if (TREE_CODE (lb) == INTEGER_CST && TREE_CODE (ub) == INTEGER_CST + && tree_int_cst_compare (lb, ub) <= 0) + ; + else + { + tree one = build_one_cst (POINTER_TYPE_P (type) ? sizetype : type); + /* Adding +1 and using LT_EXPR helps with loop latches that have a + loop iteration count of "PARAMETER - 1". For PARAMETER == 0 this + becomes 2^k-1 due to integer overflow, and the condition lb <= ub + is true, even if we do not want this. However lb < ub + 1 is false, + as expected. */ + tree ub_one = fold_build2 (POINTER_TYPE_P (type) + ? POINTER_PLUS_EXPR : PLUS_EXPR, + type, ub, one); + create_empty_if_region_on_edge (next_e, + fold_build2 (LT_EXPR, boolean_type_node, + lb, ub_one)); + next_e = get_true_edge_from_guard_bb (next_e->dest); + } + translate_isl_ast_for_loop (context_loop, node, next_e, type, lb, ub, ip); return last_e; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index d49bbe4..4d02ff7 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,10 @@ 2017-12-04 Richard Biener + PR tree-optimization/83255 + * gcc.dg/graphite/pr83255.c: New testcase. + +2017-12-04 Richard Biener + PR tree-optimization/83238 * gcc.dg/graphite/pr83238.c: New testcase. diff --git a/gcc/testsuite/gcc.dg/graphite/pr83255.c b/gcc/testsuite/gcc.dg/graphite/pr83255.c new file mode 100644 index 0000000..cb376fa --- /dev/null +++ b/gcc/testsuite/gcc.dg/graphite/pr83255.c @@ -0,0 +1,28 @@ +/* { dg-do run } */ +/* { dg-options "-O -floop-nest-optimize -fdump-tree-graphite-details" } */ + +int rx, in; + +int +main (void) +{ + const int tj = 3; + int as[tj]; + static int l4; + + while (l4 < 1) + { + for (rx = 0; rx < tj; ++rx) + { + for (in = 0; in < tj; ++in) + as[in] = 1; + as[rx] = 0; + } + ++l4; + } + + if (as[tj - 1] != 0) + __builtin_abort (); +} + +/* { dg-final { scan-tree-dump "loop nest optimized" "graphite" } } */ -- 2.7.4