> -----Original Message-----
> From: gcc-patches-ow...@gcc.gnu.org [mailto:gcc-patches-
> ow...@gcc.gnu.org] On Behalf Of Jiangning Liu
> Sent: Friday, January 20, 2012 5:07 PM
> To: 'Richard Guenther'
> Cc: gcc-patches@gcc.gnu.org
> Subject: RE: [PATCH] Improve SCEV for array element
>
> > It's definitely not ok at this stage but at most for next stage1.
>
> OK. I may wait until next stage1.
>
> > This is a very narrow pattern-match. It doesn't allow for &a[i].x
> for
> > example, even if a[i] is a one-element structure. I think the
> > canonical way of handling ADDR_EXPR is to use sth like
> >
> > base = get_inner_reference (TREE_OPERAND (rhs1, 0), ..., &offset,
> > ...); base = build1 (ADDR_EXPR, TREE_TYPE (rhs1), base);
> > chrec1 = analyze_scalar_evolution (loop, base);
> > chrec2 = analyze_scalar_evolution (loop, offset);
> > chrec1 = chrec_convert (type, chrec1, at_stmt);
> > chrec2 = chrec_convert (TREE_TYPE (offset), chrec2, at_stmt);
> > res = chrec_fold_plus (type, chrec1, chrec2);
> >
> > where you probably need to handle scev_not_known when analyzing
> offset
> > (which might be NULL). You also need to add bitpos to the base
> > address (in bytes, of course). Note that the &MEM_REF case would
> > naturally work with this as well.
>
> OK. New patch is like below, and bootstrapped on x86-32.
>
> ChangeLog:
>
> 2012-01-20 Jiangning Liu <jiangning....@arm.com>
>
> * tree-scalar-evolution (interpret_rhs_expr): generate chrec
> for
> array reference and component reference.
>
>
> ChangeLog for testsuite:
>
> 2012-01-20 Jiangning Liu <jiangning....@arm.com>
>
> * gcc.dg/tree-ssa/scev-3.c: New.
> * gcc.dg/tree-ssa/scev-4.c: New.
>
Richard,
PING... Is this patch OK after branch 4.7 is created and trunk is open
again?
Thanks,
-Jiangning
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/scev-3.c
> b/gcc/testsuite/gcc.dg/tree-ssa/scev-3.c
> new file mode 100644
> index 0000000..28d5c93
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/scev-3.c
> @@ -0,0 +1,18 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +
> +int *a_p;
> +int a[1000];
> +
> +f(int k)
> +{
> + int i;
> +
> + for (i=k; i<1000; i+=k) {
> + a_p = &a[i];
> + *a_p = 100;
> + }
> +}
> +
> +/* { dg-final { scan-tree-dump-times "&a" 1 "optimized" } } */
> +/* { dg-final { cleanup-tree-dump "optimized" } } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/scev-4.c
> b/gcc/testsuite/gcc.dg/tree-ssa/scev-4.c
> new file mode 100644
> index 0000000..6c1e530
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/scev-4.c
> @@ -0,0 +1,23 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +
> +typedef struct {
> + int x;
> + int y;
> +} S;
> +
> +int *a_p;
> +S a[1000];
> +
> +f(int k)
> +{
> + int i;
> +
> + for (i=k; i<1000; i+=k) {
> + a_p = &a[i].y;
> + *a_p = 100;
> + }
> +}
> +
> +/* { dg-final { scan-tree-dump-times "&a" 1 "optimized" } } */
> +/* { dg-final { cleanup-tree-dump "optimized" } } */
> diff --git a/gcc/tree-scalar-evolution.c b/gcc/tree-scalar-evolution.c
> index 2077c8d..4e06b75
> --- a/gcc/tree-scalar-evolution.c
> +++ b/gcc/tree-scalar-evolution.c
> @@ -1712,16 +1712,61 @@ interpret_rhs_expr (struct loop *loop, gimple
> at_stmt,
> switch (code)
> {
> case ADDR_EXPR:
> - /* Handle &MEM[ptr + CST] which is equivalent to
> POINTER_PLUS_EXPR.
> */
> - if (TREE_CODE (TREE_OPERAND (rhs1, 0)) != MEM_REF)
> - {
> - res = chrec_dont_know;
> - break;
> - }
> + if (TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF
> + || TREE_CODE (TREE_OPERAND (rhs1, 0)) == MEM_REF
> + || TREE_CODE (TREE_OPERAND (rhs1, 0)) == COMPONENT_REF)
> + {
> + enum machine_mode mode;
> + HOST_WIDE_INT bitsize, bitpos;
> + int unsignedp;
> + int volatilep = 0;
> + tree base, offset;
> + tree chrec3;
> +
> + base = get_inner_reference (TREE_OPERAND (rhs1, 0),
> + &bitsize, &bitpos, &offset,
> + &mode, &unsignedp, &volatilep, false);
> +
> + if (TREE_CODE (base) == MEM_REF)
> + {
> + rhs2 = TREE_OPERAND (base, 1);
> + rhs1 = TREE_OPERAND (base, 0);
> +
> + chrec1 = analyze_scalar_evolution (loop, rhs1);
> + chrec2 = analyze_scalar_evolution (loop, rhs2);
> + chrec1 = chrec_convert (type, chrec1, at_stmt);
> + chrec2 = chrec_convert (TREE_TYPE (rhs2), chrec2, at_stmt);
> + res = chrec_fold_plus (type, chrec1, chrec2);
> + }
> + else
> + {
> + base = build1 (ADDR_EXPR, TREE_TYPE (rhs1), base);
> + chrec1 = analyze_scalar_evolution (loop, base);
> + chrec1 = chrec_convert (type, chrec1, at_stmt);
> + res = chrec1;
> + }
>
> - rhs2 = TREE_OPERAND (TREE_OPERAND (rhs1, 0), 1);
> - rhs1 = TREE_OPERAND (TREE_OPERAND (rhs1, 0), 0);
> - /* Fall through. */
> + if (offset != NULL_TREE)
> + {
> + chrec2 = analyze_scalar_evolution (loop, offset);
> + chrec2 = chrec_convert (TREE_TYPE (offset), chrec2, at_stmt);
> + res = chrec_fold_plus (type, res, chrec2);
> + }
> +
> + if (bitpos)
> + {
> + gcc_assert ((bitpos % BITS_PER_UNIT) == 0);
> +
> + chrec3 = build_int_cst (integer_type_node,
> + bitpos / BITS_PER_UNIT);
> + chrec3 = analyze_scalar_evolution (loop, chrec3);
> + chrec3 = chrec_convert (integer_type_node, chrec3, at_stmt);
> + res = chrec_fold_plus (type, res, chrec3);
> + }
> + }
> + else
> + res = chrec_dont_know;
> + break;
>
> case POINTER_PLUS_EXPR:
> chrec1 = analyze_scalar_evolution (loop, rhs1);
>
> Thanks,
> -Jiangning
