This fixes the wrong-code caused by the use-before-compute
of GROUP_READ_WRITE_DEPENDENCE after I moved data dependence
checking after group analysis in the vectorizer. The fix
is to move the dependence checking completely to the
dependence checking - now possible as we have computed groups
already.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
Richard.
2013-04-15 Richard Biener <rguent...@suse.de>
PR tree-optimization/56933
* tree-vectorizer.h (struct _stmt_vec_info): Remove read_write_dep
member.
(GROUP_READ_WRITE_DEPENDENCE): Remove.
(STMT_VINFO_GROUP_READ_WRITE_DEPENDENCE): Likewise.
* tree-vect-data-refs.c (vect_analyze_group_access): Move
dependence check ...
vect_analyze_data_ref_dependence (vect_analyze_data_ref_dependence):
... here.
* tree-vect-stmts.c (new_stmt_vec_info): Do not initialize
GROUP_READ_WRITE_DEPENDENCE.
* gcc.dg/vect/pr56933.c: New testcase.
Index: gcc/tree-vect-data-refs.c
===================================================================
*** gcc/tree-vect-data-refs.c (revision 197957)
--- gcc/tree-vect-data-refs.c (working copy)
*************** vect_analyze_data_ref_dependence (struct
*** 341,354 ****
dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (drb));
}
! /* For interleaving, mark that there is a read-write dependency if
! necessary. We check before that one of the data-refs is store.
*/
! if (DR_IS_READ (dra))
! GROUP_READ_WRITE_DEPENDENCE (stmtinfo_a) = true;
! else
! {
! if (DR_IS_READ (drb))
! GROUP_READ_WRITE_DEPENDENCE (stmtinfo_b) = true;
}
continue;
--- 341,374 ----
dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (drb));
}
! /* When we perform grouped accesses and perform implicit CSE
! by detecting equal accesses and doing disambiguation with
! runtime alias tests like for
! .. = a[i];
! .. = a[i+1];
! a[i] = ..;
! a[i+1] = ..;
! *p = ..;
! .. = a[i];
! .. = a[i+1];
! where we will end up loading { a[i], a[i+1] } once, make
! sure that inserting group loads before the first load and
! stores after the last store will do the right thing. */
! if ((STMT_VINFO_GROUPED_ACCESS (stmtinfo_a)
! && GROUP_SAME_DR_STMT (stmtinfo_a))
! || (STMT_VINFO_GROUPED_ACCESS (stmtinfo_b)
! && GROUP_SAME_DR_STMT (stmtinfo_b)))
! {
! gimple earlier_stmt;
! earlier_stmt = get_earlier_stmt (DR_STMT (dra), DR_STMT (drb));
! if (DR_IS_WRITE
! (STMT_VINFO_DATA_REF (vinfo_for_stmt (earlier_stmt))))
! {
! if (dump_enabled_p ())
! dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
! "READ_WRITE dependence in interleaving.");
! return true;
! }
}
continue;
*************** vect_analyze_group_access (struct data_r
*** 2097,2113 ****
return false;
}
- /* Check that there is no load-store dependencies for this loads
- to prevent a case of load-store-load to the same location.
*/
- if (GROUP_READ_WRITE_DEPENDENCE (vinfo_for_stmt (next))
- || GROUP_READ_WRITE_DEPENDENCE (vinfo_for_stmt (prev)))
- {
- if (dump_enabled_p ())
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
- "READ_WRITE dependence in
interleaving.");
- return false;
- }
-
/* For load use the same data-ref load. */
GROUP_SAME_DR_STMT (vinfo_for_stmt (next)) = prev;
--- 2117,2122 ----
Index: gcc/tree-vect-stmts.c
===================================================================
*** gcc/tree-vect-stmts.c (revision 197957)
--- gcc/tree-vect-stmts.c (working copy)
*************** new_stmt_vec_info (gimple stmt, loop_vec
*** 5962,5968 ****
GROUP_STORE_COUNT (res) = 0;
GROUP_GAP (res) = 0;
GROUP_SAME_DR_STMT (res) = NULL;
- GROUP_READ_WRITE_DEPENDENCE (res) = false;
return res;
}
--- 5962,5967 ----
Index: gcc/tree-vectorizer.h
===================================================================
*** gcc/tree-vectorizer.h (revision 197957)
--- gcc/tree-vectorizer.h (working copy)
*************** typedef struct _stmt_vec_info {
*** 460,469 ****
/* Stmt is part of some pattern (computation idiom) */
bool in_pattern_p;
- /* For loads only, if there is a store with the same location, this field is
- TRUE. */
- bool read_write_dep;
-
/* The stmt to which this info struct refers to. */
gimple stmt;
--- 460,465 ----
*************** typedef struct _stmt_vec_info {
*** 589,595 ****
#define STMT_VINFO_GROUP_STORE_COUNT(S) (S)->store_count
#define STMT_VINFO_GROUP_GAP(S) (S)->gap
#define STMT_VINFO_GROUP_SAME_DR_STMT(S) (S)->same_dr_stmt
- #define STMT_VINFO_GROUP_READ_WRITE_DEPENDENCE(S) (S)->read_write_dep
#define STMT_VINFO_GROUPED_ACCESS(S) ((S)->first_element != NULL &&
(S)->data_ref_info)
#define STMT_VINFO_LOOP_PHI_EVOLUTION_PART(S) (S)->loop_phi_evolution_part
--- 585,590 ----
*************** typedef struct _stmt_vec_info {
*** 599,605 ****
#define GROUP_STORE_COUNT(S) (S)->store_count
#define GROUP_GAP(S) (S)->gap
#define GROUP_SAME_DR_STMT(S) (S)->same_dr_stmt
- #define GROUP_READ_WRITE_DEPENDENCE(S) (S)->read_write_dep
#define STMT_VINFO_RELEVANT_P(S) ((S)->relevant !=
vect_unused_in_scope)
--- 594,599 ----
Index: gcc/testsuite/gcc.dg/vect/pr56933.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/pr56933.c (revision 0)
--- gcc/testsuite/gcc.dg/vect/pr56933.c (working copy)
***************
*** 0 ****
--- 1,40 ----
+ /* { dg-do run } */
+
+ extern void abort (void);
+ void __attribute__((noinline,noclone))
+ foo (double *b, double *d, double *f)
+ {
+ int i;
+ for (i = 0; i < 1024; i++)
+ {
+ d[2*i] = 2. * d[2*i];
+ d[2*i+1] = 4. * d[2*i+1];
+ b[i] = d[2*i] - 1.;
+ f[i] = d[2*i+1] + 2.;
+ }
+ }
+ int main()
+ {
+ double b[1024], d[2*1024], f[1024];
+ int i;
+ for (i = 0; i < 2*1024; i++)
+ d[i] = 1.;
+ foo (b, d, f);
+ for (i = 0; i < 1024; i+= 2)
+ {
+ if (d[2*i] != 2.)
+ abort ();
+ if (d[2*i+1] != 4.)
+ abort ();
+ }
+ for (i = 0; i < 1024; i++)
+ {
+ if (b[i] != 1.)
+ abort ();
+ if (f[i] != 6.)
+ abort ();
+ }
+ return 0;
+ }
+
+ /* { dg-final { cleanup-tree-dump "vect" } } */
