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Check array indices in object_address_invariant_in_loop_p (PR 84357)
- From: Richard Sandiford <richard dot sandiford at linaro dot org>
- To: gcc-patches at gcc dot gnu dot org
- Date: Wed, 14 Feb 2018 09:44:10 +0000
- Subject: Check array indices in object_address_invariant_in_loop_p (PR 84357)
- Authentication-results: sourceware.org; auth=none
object_address_invariant_in_loop_p ignored ARRAY_REF indices on
the basis that:
/* Index of the ARRAY_REF was zeroed in analyze_indices, thus we only
need to check the stride and the lower bound of the reference. */
That was true back in 2007 when the code was added:
static void
dr_analyze_indices (struct data_reference *dr, struct loop *nest)
{
[...]
while (handled_component_p (aref))
{
if (TREE_CODE (aref) == ARRAY_REF)
{
op = TREE_OPERAND (aref, 1);
access_fn = analyze_scalar_evolution (loop, op);
access_fn = resolve_mixers (nest, access_fn);
VEC_safe_push (tree, heap, access_fns, access_fn);
TREE_OPERAND (aref, 1) = build_int_cst (TREE_TYPE (op), 0);
}
aref = TREE_OPERAND (aref, 0);
}
but the assignment was removed a few years ago. We were therefore
treating "two->arr[i]" and "three->arr[i]" as loop invariant.
Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu.
OK to install?
Richard
2018-02-14 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
PR tree-optimization/84357
* tree-data-ref.c (object_address_invariant_in_loop_p): Check
operand 1 of an ARRAY_REF too.
gcc/testsuite/
PR tree-optimization/84357
* gcc.dg/vect/pr84357.c: New test.
Index: gcc/tree-data-ref.c
===================================================================
--- gcc/tree-data-ref.c 2018-02-08 15:16:21.784407397 +0000
+++ gcc/tree-data-ref.c 2018-02-14 09:42:14.801095011 +0000
@@ -2200,13 +2200,10 @@ object_address_invariant_in_loop_p (cons
{
if (TREE_CODE (obj) == ARRAY_REF)
{
- /* Index of the ARRAY_REF was zeroed in analyze_indices, thus we only
- need to check the stride and the lower bound of the reference. */
- if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 2),
- loop->num)
- || chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 3),
- loop->num))
- return false;
+ for (int i = 1; i < 4; ++i)
+ if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, i),
+ loop->num))
+ return false;
}
else if (TREE_CODE (obj) == COMPONENT_REF)
{
Index: gcc/testsuite/gcc.dg/vect/pr84357.c
===================================================================
--- /dev/null 2018-02-10 09:05:46.714416790 +0000
+++ gcc/testsuite/gcc.dg/vect/pr84357.c 2018-02-14 09:42:14.800095067 +0000
@@ -0,0 +1,31 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-Wall" } */
+
+#define COUNT 32
+
+typedef struct s1 {
+ unsigned char c;
+} s1;
+
+typedef struct s2
+{
+ char pad;
+ s1 arr[COUNT];
+} s2;
+
+typedef struct s3 {
+ s1 arr[COUNT];
+} s3;
+
+s2 * get_s2();
+s3 * gActiveS3;
+void foo()
+{
+ s3 * three = gActiveS3;
+ s2 * two = get_s2();
+
+ for (int i = 0; i < COUNT; i++)
+ {
+ two->arr[i].c = three->arr[i].c;
+ }
+}