Re: Minor loop-iv tweaks for doloops

[Richard Guenther <richard dot guenther at gmail dot com>]

On Sun, Sep 27, 2009 at 1:40 AM, Bernd Schmidt <bernds_cb1@t-online.de> wrote:
> This allows us to generate slightly more hardware loops on the Blackfin.
> ?When walking through arrays on the stack, we often generate comparisons
> based on the stack or frame pointer; we should treat these as invariant
> everywhere. ?Some earlier patches already went in that direction, this
> one just converts a few more places.
>
> Bootstrapped and regression tested on i686-linux. ?Ok?

Ok.

Thanks,
Richard.

> I'm also attaching a patch with three Blackfin-specific testcases which
> verify that we're generating hardware loops as expected.
>
>
> Bernd
> --
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>
> ? ? ? ?* loop-iv.c (iv_analyze_op): Use function_invariant_p, not CONSTANT_P,
> ? ? ? ?to test for GRD_INVARIANT.
> ? ? ? ?(simple_rhs_p): Anything that's function_invariant_p is fine.
>
> Index: loop-iv.c
> ===================================================================
> --- loop-iv.c ? (revision 152180)
> +++ loop-iv.c ? (working copy)
> @@ -1120,7 +1120,7 @@ iv_analyze_op (rtx insn, rtx op, struct
> ? ? ? print_rtl_single (dump_file, insn);
> ? ? }
>
> - ?if (CONSTANT_P (op))
> + ?if (function_invariant_p (op))
> ? ? res = GRD_INVARIANT;
> ? else if (GET_CODE (op) == SUBREG)
> ? ? {
> @@ -1329,7 +1329,7 @@ simple_rhs_p (rtx rhs)
> ?{
> ? rtx op0, op1;
>
> - ?if (CONSTANT_P (rhs)
> + ?if (function_invariant_p (rhs)
> ? ? ? || (REG_P (rhs) && !HARD_REGISTER_P (rhs)))
> ? ? return true;
>
>
> Index: testsuite/gcc.target/bfin/lsetup-1.c
> ===================================================================
> --- testsuite/gcc.target/bfin/lsetup-1.c ? ? ? ?(revision 0)
> +++ testsuite/gcc.target/bfin/lsetup-1.c ? ? ? ?(revision 0)
> @@ -0,0 +1,45 @@
> +/* { dg-do compile { target bfin-*-* } } */
> +/* { dg-options "-O2" } */
> +/* { dg-final { scan-assembler-times "LSETUP" 6 } } */
> +
> +#define SIZE 1024
> +
> +int foo (int (*x)[SIZE])
> +{
> + ? ?int i, sum = 0;
> +
> + ? ?for ?(i = 0; i < SIZE; i++) {
> + ? ? ? int j;
> + ? ? ? for (j = 0; j < SIZE; j++)
> + ? ? ? ? ? ? ? sum += x[i][j];
> + ? ?}
> +
> + ? ?return sum;
> +}
> +
> +int bar (int **x)
> +{
> + ? ?int i, sum = 0;
> +
> + ? ?for ?(i = 0; i < SIZE; i++) {
> + ? ? ? int j;
> + ? ? ? for (j = 0; j < SIZE; j++)
> + ? ? ? ? ? ? ? sum += x[i][j];
> + ? ?}
> +
> + ? ?return sum;
> +}
> +
> +int baz ()
> +{
> + ? ?int i, sum = 0;
> + ? ?int x[SIZE][SIZE];
> + ? ?fill(x);
> + ? ?for ?(i = 0; i < SIZE; i++) {
> + ? ? ? int j;
> + ? ? ? for (j = 0; j < SIZE; j++)
> + ? ? ? ? ? ? ? sum += x[i][j];
> + ? ?}
> +
> + ? ?return sum;
> +}
> Index: testsuite/gcc.target/bfin/lsetup-2.c
> ===================================================================
> --- testsuite/gcc.target/bfin/lsetup-2.c ? ? ? ?(revision 0)
> +++ testsuite/gcc.target/bfin/lsetup-2.c ? ? ? ?(revision 0)
> @@ -0,0 +1,33 @@
> +/* { dg-do compile { target bfin-*-* } } */
> +/* { dg-options "-O2" } */
> +/* { dg-final { scan-assembler-times "LSETUP" 2 } } */
> +
> +#include <stdlib.h>
> +#include <stdio.h>
> +
> +#define SIZE 1024
> +
> +void foo ()
> +{
> + ? ?int index, sum = 0, *x;
> +
> + ? ?x = malloc (SIZE);
> +
> + ? ?for ?(index = 0; index < SIZE ; index++) {
> + ? ? ? sum += x[index];
> + ? ?}
> +
> + ? ?printf("%i",sum);
> +}
> +
> +void bar ()
> +{
> + ? ?int index, sum = 0, x[SIZE];
> +
> + ? ?for ?(index = 0; index < SIZE ; index++) {
> + ? ? ? sum += x[index];
> + ? ?}
> +
> + ? ?printf("%i",sum);
> +}
> +
> Index: testsuite/gcc.target/bfin/lsetup-3.c
> ===================================================================
> --- testsuite/gcc.target/bfin/lsetup-3.c ? ? ? ?(revision 0)
> +++ testsuite/gcc.target/bfin/lsetup-3.c ? ? ? ?(revision 0)
> @@ -0,0 +1,13 @@
> +/* { dg-do compile { target bfin-*-* } } */
> +/* { dg-options "-O2" } */
> +/* { dg-final { scan-assembler "LSETUP" } } */
> +
> +void test(unsigned int start, unsigned int end)
> +{
> + ?unsigned int count;
> + ?start = start & -32;
> + ?end = end & -32;
> + ?for (count = (end - start); count; count -= 32)
> + ? ?__asm__ __volatile__("FLUSH[%0++];" :
> + ? ? ? ? ? ? ? ? ? ? ? ?"+p"(start));
> +}
>
>