re PR tree-optimization/71915 (A missed opportunity for SLSR)

[gcc]

2016-10-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/71915
	PR tree-optimization/71490
	* gimple-ssa-strength-reduction.c (struct slsr_cand_d): Add
	stride_type field.
	(find_basis_for_base_expr): Require stride types to match when
	seeking a basis.
	(alloc_cand_and_find_basis): Record the stride type.
	(slsr_process_phi): Pass stride type to alloc_cand_and_find_basis.
	(backtrace_base_for_ref): Pass types to legal_cast_p_1 rather than
	the expressions having those types.
	(slsr_process_ref): Pass stride type to alloc_cand_and_find_basis.
	(create_mul_ssa_cand): Likewise.
	(create_mul_imm_cand): Likewise.
	(create_add_ssa_cand): Likewise.
	(create_add_imm_cand): Likewise.
	(legal_cast_p_1): Change interface to accept types rather than the
	expressions having those types.
	(legal_cast_p): Pass types to legal_cast_p_1.
	(slsr_process_cast): Pass stride type to
	alloc_cand_and_find_basis.
	(slsr_process_copy): Likewise.
	(dump_candidate): Display stride type when a cast exists.
	(create_add_on_incoming_edge): Introduce a cast when necessary for
	the stride type.
	(analyze_increments): Change the code checking for invalid casts
	to rely on the stride type, and update the documentation and
	example.  Change the code checking for pointer multiplies to rely
	on the stride type.
	(insert_initializers): Introduce a cast when necessary for the
	stride type.  Use the stride type for the type of the initializer.

[gcc/testsuite]

2016-10-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/71915
	PR tree-optimization/71490
	* gcc.dg/tree-ssa/pr54245.c: Delete.
	* gcc.dg/tree-ssa/slsr-8.c: Adjust for new optimization and
	document why.

From-SVN: r241695

gcc/ChangeLog

+2016-10-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR tree-optimization/71915
+	PR tree-optimization/71490
+	* gimple-ssa-strength-reduction.c (struct slsr_cand_d): Add
+	stride_type field.
+	(find_basis_for_base_expr): Require stride types to match when
+	seeking a basis.
+	(alloc_cand_and_find_basis): Record the stride type.
+	(slsr_process_phi): Pass stride type to alloc_cand_and_find_basis.
+	(backtrace_base_for_ref): Pass types to legal_cast_p_1 rather than
+	the expressions having those types.
+	(slsr_process_ref): Pass stride type to alloc_cand_and_find_basis.
+	(create_mul_ssa_cand): Likewise.
+	(create_mul_imm_cand): Likewise.
+	(create_add_ssa_cand): Likewise.
+	(create_add_imm_cand): Likewise.
+	(legal_cast_p_1): Change interface to accept types rather than the
+	expressions having those types.
+	(legal_cast_p): Pass types to legal_cast_p_1.
+	(slsr_process_cast): Pass stride type to
+	alloc_cand_and_find_basis.
+	(slsr_process_copy): Likewise.
+	(dump_candidate): Display stride type when a cast exists.
+	(create_add_on_incoming_edge): Introduce a cast when necessary for
+	the stride type.
+	(analyze_increments): Change the code checking for invalid casts
+	to rely on the stride type, and update the documentation and
+	example.  Change the code checking for pointer multiplies to rely
+	on the stride type.
+	(insert_initializers): Introduce a cast when necessary for the
+	stride type.  Use the stride type for the type of the initializer.
+
 2016-10-30  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
 
 	* config/arm/arm.c (arm_const_not_ok_for_debug_p): Use VAR_P.

gcc/testsuite/ChangeLog

+2016-10-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR tree-optimization/71915
+	PR tree-optimization/71490
+	* gcc.dg/tree-ssa/pr54245.c: Delete.
+	* gcc.dg/tree-ssa/slsr-8.c: Adjust for new optimization and
+	document why.
+
 2016-10-30  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR fortran/78123

gcc/testsuite/gcc.dg/tree-ssa/pr54245.c

-/* { dg-do compile } */
-/* { dg-options "-O1 -fdump-tree-slsr-details" } */
-
-#include <stdio.h>
-
-#define W1  22725
-#define W2  21407
-#define W3  19266
-#define W6  8867
-
-void idct_row(short *row, int *dst)
-{
-    int a0, a1, b0, b1;
-
-    a0 = W1 * row[0];
-    a1 = a0;
-
-    a0 += W2 * row[2];
-    a1 += W6 * row[2];
-
-    b0 = W1 * row[1];
-    b1 = W3 * row[1];
-
-    dst[0] = a0 + b0;
-    dst[1] = a0 - b0;
-    dst[2] = a1 + b1;
-    dst[3] = a1 - b1;
-}
-
-static short block[8] = { 1, 2, 3, 4 };
-
-int main(void)
-{
-    int out[4];
-    int i;
-
-    idct_row(block, out);
-
-    for (i = 0; i < 4; i++)
-        printf("%d\n", out[i]);
-
-    return !(out[2] == 87858 && out[3] == 10794);
-}
-
-/* For now, disable inserting an initializer when the multiplication will
-   take place in a smaller type than originally.  This test may be deleted
-   in future when this case is handled more precisely.  */
-/* { dg-final { scan-tree-dump-times "Inserting initializer" 0 "slsr" { target { ! int16 } } } } */

gcc/testsuite/gcc.dg/tree-ssa/slsr-8.c

@@ -4,7 +4,7 @@
 /* { dg-options "-O3 -fdump-tree-optimized" } */
 
 int*
-f (int s, int *c)
+f (int s, int *c, int *d)
 {
   int a1, a2, a3, *x1, *x2, *x3;
 
@@ -14,10 +14,15 @@ f (int s, int *c)
   x2 = c - a2;
   a3 = 6 * s;
   x3 = c - a3;
-  return x1 ? x2 : x3;
+  return x1 == d ? x2 : x3;
 }
 
+/* Note that since some branch prediction heuristics changed, the
+   calculations of x2 and x3 are pushed downward into the legs
+   of the conditional, changing the code presented to SLSR.
+   However, this proves to be a useful test for introducing an
+   initializer with a cast, so we'll keep it as is.  */
+
 /* There are 4 ' * ' instances in the decls (since "int * iftmp.0;" is
-   added), 1 parm, 2 in the code.  The second one in the code can be
-   a widening mult.  */
-/* { dg-final { scan-tree-dump-times " w?\\* " 7 "optimized" } } */
+   added), 2 parms, 3 in the code.  */
+/* { dg-final { scan-tree-dump-times " \\* " 9 "optimized" } } */