From 8b432c8b8323a67de0ac1c4fce32b80a6eaef9be Mon Sep 17 00:00:00 2001
From: Alexander Monakov <amonakov@ispras.ru>
Date: Fri, 17 Dec 2010 15:54:59 +0300
Subject: [PATCH] re PR middle-end/46761 (-fgraphite-identity produces wrong
code for array initialization arr[i] = i)
PR middle-end/46761
* graphite-clast-to-gimple.c (graphite_create_new_loop_guard): Prefer
to use unadjusted UB.
testsuite:
* gcc.dg/graphite/pr46761.c: New.
From-SVN: r167980
---
gcc/ChangeLog | 6 ++++++
gcc/graphite-clast-to-gimple.c | 28 ++++++++++++++-----------
gcc/testsuite/ChangeLog | 5 +++++
gcc/testsuite/gcc.dg/graphite/pr46761.c | 22 +++++++++++++++++++
4 files changed, 49 insertions(+), 12 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/graphite/pr46761.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 571760f8f814..c5e80126a940 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2010-12-17 Alexander Monakov <amonakov@ispras.ru>
+
+ PR middle-end/46761
+ * graphite-clast-to-gimple.c (graphite_create_new_loop_guard): Prefer
+ to use unadjusted UB.
+
2010-12-17 Dodji Seketeli <dodji@redhat.com>
* dwarf2out.c (gen_type_die_with_usage): Do not try to emit debug
diff --git a/gcc/graphite-clast-to-gimple.c b/gcc/graphite-clast-to-gimple.c
index eef5ad16abdb..0937fc8eb94a 100644
--- a/gcc/graphite-clast-to-gimple.c
+++ b/gcc/graphite-clast-to-gimple.c
@@ -975,20 +975,24 @@ graphite_create_new_loop_guard (sese region, edge entry_edge,
newivs_index, params_index);
tree ub = clast_to_gcc_expression (type, stmt->UB, region, newivs,
newivs_index, params_index);
- tree one = POINTER_TYPE_P (type) ? size_one_node
- : fold_convert (type, integer_one_node);
- /* 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^{32|64}, 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);
-
- /* When ub + 1 wraps around, use lb <= ub. */
- if (integer_zerop (ub_one))
+ /* When ub is simply a constant or a parameter, use lb <= ub. */
+ if (TREE_CODE (ub) == INTEGER_CST || TREE_CODE (ub) == SSA_NAME)
cond_expr = fold_build2 (LE_EXPR, boolean_type_node, lb, ub);
else
- cond_expr = fold_build2 (LT_EXPR, boolean_type_node, lb, ub_one);
+ {
+ tree one = (POINTER_TYPE_P (type)
+ ? size_one_node
+ : fold_convert (type, integer_one_node));
+ /* 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);
+
+ cond_expr = fold_build2 (LT_EXPR, boolean_type_node, lb, ub_one);
+ }
exit_edge = create_empty_if_region_on_edge (entry_edge, cond_expr);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e32bf6e04d0c..67799d0d9a7a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2010-12-17 Alexander Monakov <amonakov@ispras.ru>
+
+ PR middle-end/46761
+ * gcc.dg/graphite/pr46761.c: New.
+
2010-12-17 Janus Weil <janus@gcc.gnu.org>
PR fortran/46849
diff --git a/gcc/testsuite/gcc.dg/graphite/pr46761.c b/gcc/testsuite/gcc.dg/graphite/pr46761.c
new file mode 100644
index 000000000000..f45398a2b479
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/graphite/pr46761.c
@@ -0,0 +1,22 @@
+/* { dg-do run } */
+/* { dg-options "-O -fgraphite-identity" } */
+
+#define N 128
+
+int
+main ()
+{
+ int arr[N], i, s = 0;
+ for (i = 0; i < N; i++)
+ arr[i] = i;
+
+ for (i = 0; i < N; i++)
+ if (arr[i] != i)
+ __builtin_abort ();
+
+ for (i = 0; i < N; i++)
+ s += arr[i];
+ if (s != (N * (N - 1)) / 2)
+ __builtin_abort ();
+ return 0;
+}
--
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