diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 80b48764948c223c16b8c67a407abfbf1b79d78c..8592db99d6fc34aee5b8c201c98772366d5b83d1 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,24 @@
+2009-07-23 Paul Thomas <pault@gcc.gnu.org>
+
+ PR fortran/24524
+ * trans-array.c (gfc_init_loopinfo): Initialize the reverse
+ field.
+ gfc_trans_scalarized_loop_end: If reverse set in dimension n,
+ reverse the scalarization loop.
+ gfc_conv_resolve_dependencies: Pass the reverse field of the
+ loopinfo to gfc_dep_resolver.
+ trans-expr.c (gfc_trans_assignment_1): Enable loop reversal for
+ assignment by resetting loop.reverse.
+ gfortran.h : Add the gfc_reverse enum.
+ trans.h : Add the reverse field to gfc_loopinfo.
+ dependency.c (gfc_check_dependency): Pass null to the new arg
+ of gfc_dep_resolver.
+ (gfc_check_section_vs_section): Check for reverse dependencies.
+ (gfc_dep_resolver): Add reverse argument and deal with the loop
+ reversal logic.
+ dependency.h : Modify prototype for gfc_dep_resolver to include
+ gfc_reverse *.
+
2010-07-23 Daniel Kraft <d@domob.eu>
PR fortran/44709
diff --git a/gcc/fortran/dependency.c b/gcc/fortran/dependency.c
index c21a2e43588be642f8487f9a75ca7e4e688f40e5..9dd4d9c46729917382e3ada8bcdfda876492b2fd 100644
--- a/gcc/fortran/dependency.c
+++ b/gcc/fortran/dependency.c
@@ -39,7 +39,8 @@ typedef enum
{
GFC_DEP_ERROR,
GFC_DEP_EQUAL, /* Identical Ranges. */
- GFC_DEP_FORWARD, /* e.g., a(1:3), a(2:4). */
+ GFC_DEP_FORWARD, /* e.g., a(1:3) = a(2:4). */
+ GFC_DEP_BACKWARD, /* e.g. a(2:4) = a(1:3). */
GFC_DEP_OVERLAP, /* May overlap in some other way. */
GFC_DEP_NODEP /* Distinct ranges. */
}
@@ -831,7 +832,7 @@ gfc_check_dependency (gfc_expr *expr1, gfc_expr *expr2, bool identical)
/* Identical and disjoint ranges return 0,
overlapping ranges return 1. */
if (expr1->ref && expr2->ref)
- return gfc_dep_resolver (expr1->ref, expr2->ref);
+ return gfc_dep_resolver (expr1->ref, expr2->ref, NULL);
return 1;
@@ -1074,6 +1075,30 @@ gfc_check_section_vs_section (gfc_ref *lref, gfc_ref *rref, int n)
return GFC_DEP_FORWARD;
}
+ /* Check for backward dependencies:
+ Are the strides the same?. */
+ if ((!l_stride && !r_stride)
+ ||
+ (l_stride && r_stride
+ && gfc_dep_compare_expr (l_stride, r_stride) == 0))
+ {
+ /* x:y vs. x+1:z. */
+ if (l_dir == 1 && r_dir == 1
+ && l_start && r_start
+ && gfc_dep_compare_expr (l_start, r_start) == 1
+ && l_end && r_end
+ && gfc_dep_compare_expr (l_end, r_end) == 1)
+ return GFC_DEP_BACKWARD;
+
+ /* x:y:-1 vs. x-1:z:-1. */
+ if (l_dir == -1 && r_dir == -1
+ && l_start && r_start
+ && gfc_dep_compare_expr (l_start, r_start) == -1
+ && l_end && r_end
+ && gfc_dep_compare_expr (l_end, r_end) == -1)
+ return GFC_DEP_BACKWARD;
+ }
+
return GFC_DEP_OVERLAP;
}
@@ -1481,16 +1506,19 @@ ref_same_as_full_array (gfc_ref *full_ref, gfc_ref *ref)
/* Finds if two array references are overlapping or not.
Return value
+ 2 : array references are overlapping but reversal of one or
+ more dimensions will clear the dependency.
1 : array references are overlapping.
0 : array references are identical or not overlapping. */
int
-gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref)
+gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref, gfc_reverse *reverse)
{
int n;
gfc_dependency fin_dep;
gfc_dependency this_dep;
+ this_dep = GFC_DEP_ERROR;
fin_dep = GFC_DEP_ERROR;
/* Dependencies due to pointers should already have been identified.
We only need to check for overlapping array references. */
@@ -1543,6 +1571,7 @@ gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref)
if (lref->u.ar.dimen_type[n] == DIMEN_VECTOR
|| rref->u.ar.dimen_type[n] == DIMEN_VECTOR)
return 1;
+
if (lref->u.ar.dimen_type[n] == DIMEN_RANGE
&& rref->u.ar.dimen_type[n] == DIMEN_RANGE)
this_dep = gfc_check_section_vs_section (lref, rref, n);
@@ -1563,6 +1592,38 @@ gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref)
if (this_dep == GFC_DEP_NODEP)
return 0;
+ /* Now deal with the loop reversal logic: This only works on
+ ranges and is activated by setting
+ reverse[n] == GFC_CAN_REVERSE
+ The ability to reverse or not is set by previous conditions
+ in this dimension. If reversal is not activated, the
+ value GFC_DEP_BACKWARD is reset to GFC_DEP_OVERLAP. */
+ if (rref->u.ar.dimen_type[n] == DIMEN_RANGE
+ && lref->u.ar.dimen_type[n] == DIMEN_RANGE)
+ {
+ /* Set reverse if backward dependence and not inhibited. */
+ if (reverse && reverse[n] != GFC_CANNOT_REVERSE)
+ reverse[n] = (this_dep == GFC_DEP_BACKWARD) ?
+ GFC_REVERSE_SET : reverse[n];
+
+ /* Inhibit loop reversal if dependence not compatible. */
+ if (reverse && reverse[n] != GFC_REVERSE_NOT_SET
+ && this_dep != GFC_DEP_EQUAL
+ && this_dep != GFC_DEP_BACKWARD
+ && this_dep != GFC_DEP_NODEP)
+ {
+ reverse[n] = GFC_CANNOT_REVERSE;
+ if (this_dep != GFC_DEP_FORWARD)
+ this_dep = GFC_DEP_OVERLAP;
+ }
+
+ /* If no intention of reversing or reversing is explicitly
+ inhibited, convert backward dependence to overlap. */
+ if ((reverse == NULL && this_dep == GFC_DEP_BACKWARD)
+ || (reverse && reverse[n] == GFC_CANNOT_REVERSE))
+ this_dep = GFC_DEP_OVERLAP;
+ }
+
/* Overlap codes are in order of priority. We only need to
know the worst one.*/
if (this_dep > fin_dep)
@@ -1578,7 +1639,7 @@ gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref)
/* Exactly matching and forward overlapping ranges don't cause a
dependency. */
- if (fin_dep < GFC_DEP_OVERLAP)
+ if (fin_dep < GFC_DEP_BACKWARD)
return 0;
/* Keep checking. We only have a dependency if
diff --git a/gcc/fortran/dependency.h b/gcc/fortran/dependency.h
index dd786bedabacb144717b5b5c84aa69b6e344d617..bac2749093b522a1e90c516eeb8cdd18f95e5f98 100644
--- a/gcc/fortran/dependency.h
+++ b/gcc/fortran/dependency.h
@@ -29,7 +29,6 @@ typedef enum
}
gfc_dep_check;
-
/*********************** Functions prototypes **************************/
bool gfc_ref_needs_temporary_p (gfc_ref *);
@@ -41,6 +40,6 @@ int gfc_check_dependency (gfc_expr *, gfc_expr *, bool);
int gfc_is_same_range (gfc_array_ref *, gfc_array_ref *, int, int);
int gfc_expr_is_one (gfc_expr *, int);
-int gfc_dep_resolver(gfc_ref *, gfc_ref *);
+int gfc_dep_resolver(gfc_ref *, gfc_ref *, gfc_reverse *);
int gfc_are_equivalenced_arrays (gfc_expr *, gfc_expr *);
diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
index 401e501c41ddcad7993a99246938206c7ffd1af8..a493866ab3691848adf49cb2d45a449a68f43ccb 100644
--- a/gcc/fortran/gfortran.h
+++ b/gcc/fortran/gfortran.h
@@ -576,6 +576,15 @@ typedef enum
}
gfc_fcoarray;
+typedef enum
+{
+ GFC_REVERSE_NOT_SET,
+ GFC_REVERSE_SET,
+ GFC_CAN_REVERSE,
+ GFC_CANNOT_REVERSE
+}
+gfc_reverse;
+
/************************* Structures *****************************/
/* Used for keeping things in balanced binary trees. */
diff --git a/gcc/fortran/trans-array.c b/gcc/fortran/trans-array.c
index d4f1cdf8f6783b84a3b411d1a6a0aca83106b61c..cca4ecc4d9c5c83e5e5687e269e4c67eb78c340e 100644
--- a/gcc/fortran/trans-array.c
+++ b/gcc/fortran/trans-array.c
@@ -2180,9 +2180,12 @@ gfc_init_loopinfo (gfc_loopinfo * loop)
gfc_init_block (&loop->pre);
gfc_init_block (&loop->post);
- /* Initially scalarize in order. */
+ /* Initially scalarize in order and default to no loop reversal. */
for (n = 0; n < GFC_MAX_DIMENSIONS; n++)
- loop->order[n] = n;
+ {
+ loop->order[n] = n;
+ loop->reverse[n] = GFC_CANNOT_REVERSE;
+ }
loop->ss = gfc_ss_terminator;
}
@@ -2842,8 +2845,18 @@ gfc_trans_scalarized_loop_end (gfc_loopinfo * loop, int n,
}
else
{
+ bool reverse_loop = (loop->reverse[n] == GFC_REVERSE_SET)
+ && (loop->temp_ss == NULL);
+
loopbody = gfc_finish_block (pbody);
+ if (reverse_loop)
+ {
+ tmp = loop->from[n];
+ loop->from[n] = loop->to[n];
+ loop->to[n] = tmp;
+ }
+
/* Initialize the loopvar. */
if (loop->loopvar[n] != loop->from[n])
gfc_add_modify (&loop->code[n], loop->loopvar[n], loop->from[n]);
@@ -2854,8 +2867,8 @@ gfc_trans_scalarized_loop_end (gfc_loopinfo * loop, int n,
gfc_init_block (&block);
/* The exit condition. */
- cond = fold_build2 (GT_EXPR, boolean_type_node,
- loop->loopvar[n], loop->to[n]);
+ cond = fold_build2 (reverse_loop ? LT_EXPR : GT_EXPR,
+ boolean_type_node, loop->loopvar[n], loop->to[n]);
tmp = build1_v (GOTO_EXPR, exit_label);
TREE_USED (exit_label) = 1;
tmp = build3_v (COND_EXPR, cond, tmp, build_empty_stmt (input_location));
@@ -2865,8 +2878,10 @@ gfc_trans_scalarized_loop_end (gfc_loopinfo * loop, int n,
gfc_add_expr_to_block (&block, loopbody);
/* Increment the loopvar. */
- tmp = fold_build2 (PLUS_EXPR, gfc_array_index_type,
- loop->loopvar[n], gfc_index_one_node);
+ tmp = fold_build2 (reverse_loop ? MINUS_EXPR : PLUS_EXPR,
+ gfc_array_index_type, loop->loopvar[n],
+ gfc_index_one_node);
+
gfc_add_modify (&block, loop->loopvar[n], tmp);
/* Build the loop. */
@@ -3449,7 +3464,8 @@ gfc_conv_resolve_dependencies (gfc_loopinfo * loop, gfc_ss * dest,
lref = dest->expr->ref;
rref = ss->expr->ref;
- nDepend = gfc_dep_resolver (lref, rref);
+ nDepend = gfc_dep_resolver (lref, rref, &loop->reverse[0]);
+
if (nDepend == 1)
break;
#if 0
diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index 09ad110ff48c1d2dd24b0103fa5c787a70716cc4..a83d4b3eda4d07c79d08af6bd86cbacc1f824d35 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -5303,6 +5303,7 @@ gfc_trans_assignment_1 (gfc_expr * expr1, gfc_expr * expr2, bool init_flag,
bool l_is_temp;
bool scalar_to_array;
tree string_length;
+ int n;
/* Assignment of the form lhs = rhs. */
gfc_start_block (&block);
@@ -5348,6 +5349,9 @@ gfc_trans_assignment_1 (gfc_expr * expr1, gfc_expr * expr2, bool init_flag,
/* Calculate the bounds of the scalarization. */
gfc_conv_ss_startstride (&loop);
+ /* Enable loop reversal. */
+ for (n = 0; n < loop.dimen; n++)
+ loop.reverse[n] = GFC_REVERSE_NOT_SET;
/* Resolve any data dependencies in the statement. */
gfc_conv_resolve_dependencies (&loop, lss, rss);
/* Setup the scalarizing loops. */
diff --git a/gcc/fortran/trans.h b/gcc/fortran/trans.h
index cbed52b5f870121fcdb29394abd946654baa84d7..9872e83df9e75074050125011ad19a3ebd7b51e1 100644
--- a/gcc/fortran/trans.h
+++ b/gcc/fortran/trans.h
@@ -240,6 +240,9 @@ typedef struct gfc_loopinfo
/* Order in which the dimensions should be looped, innermost first. */
int order[GFC_MAX_DIMENSIONS];
+ /* Enum to control loop reversal. */
+ gfc_reverse reverse[GFC_MAX_DIMENSIONS];
+
/* The number of dimensions for which a temporary is used. */
int temp_dim;