On Tue, 1 Oct 2024, Qing Zhao wrote:
> From: Richard Biener <rguent...@suse.de>
>
> Hi, this is the backport of the fix for PR116585 to GCC13.
> bootstrapped and regress tested on both X86 and aarch64.
>
> Okay for committing?
OK.
> thanks.
>
> Qing.
>
> =======
> split_constant_offset when looking through SSA defs can end up
> picking SSA leafs that are subject to abnormal coalescing. This
> can lead to downstream consumers to insert code based on the
> result (like from dataref analysis) in places that violate constraints
> for abnormal coalescing. It's best to not expand defs whose operands
> are subject to abnormal coalescing - and not either do something when
> a subexpression has operands like that already.
>
> PR tree-optimization/116585
> * tree-data-ref.cc (split_constant_offset_1): When either
> operand is subject to abnormal coalescing do no further
> processing.
>
> * gcc.dg/torture/pr116585.c: New testcase.
>
> (cherry picked from commit 1d0cb3b5fca69b81e69cfdb4aea0eebc1ac04750)
> ---
> gcc/testsuite/gcc.dg/torture/pr116585.c | 32 +++++++++++++++++++++++++
> gcc/tree-data-ref.cc | 11 ++++++---
> 2 files changed, 40 insertions(+), 3 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/torture/pr116585.c
>
> diff --git a/gcc/testsuite/gcc.dg/torture/pr116585.c
> b/gcc/testsuite/gcc.dg/torture/pr116585.c
> new file mode 100644
> index 00000000000..108c481e104
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/torture/pr116585.c
> @@ -0,0 +1,32 @@
> +/* { dg-do compile } */
> +
> +char *s1, *s2;
> +extern int* my_alloc (int);
> +extern int _setjmp ();
> +extern void bar();
> +void foo(int s1len, int s2len)
> +{
> + int e;
> + e = _setjmp ();
> + {
> + int l, i;
> + int *md = my_alloc(((sizeof(int)) * (s1len + 1) * (s2len)));
> + s1len++;
> + for (; s1len; l)
> + for (; s2len; l)
> + for (; s1len; i)
> + {
> + int j = 1;
> + for (; j < s2len; j++)
> + {
> + int cost;
> + if (s1[1] == s2[1])
> + cost = 0;
> + else
> + cost = 1;
> + md[j * s1len ] = ((cost));
> + }
> + }
> + bar();
> + }
> +}
> diff --git a/gcc/tree-data-ref.cc b/gcc/tree-data-ref.cc
> index 96934addff1..7657eeaf9e6 100644
> --- a/gcc/tree-data-ref.cc
> +++ b/gcc/tree-data-ref.cc
> @@ -763,6 +763,14 @@ split_constant_offset_1 (tree type, tree op0, enum
> tree_code code, tree op1,
> if (INTEGRAL_TYPE_P (type) && TYPE_OVERFLOW_TRAPS (type))
> return false;
>
> + if (TREE_CODE (op0) == SSA_NAME
> + && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0))
> + return false;
> + if (op1
> + && TREE_CODE (op1) == SSA_NAME
> + && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op1))
> + return false;
> +
> switch (code)
> {
> case INTEGER_CST:
> @@ -855,9 +863,6 @@ split_constant_offset_1 (tree type, tree op0, enum
> tree_code code, tree op1,
>
> case SSA_NAME:
> {
> - if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0))
> - return false;
> -
> gimple *def_stmt = SSA_NAME_DEF_STMT (op0);
> enum tree_code subcode;
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
