* [PATCH] Fix PR70013
@ 2016-03-11 10:14 Alan Lawrence
2016-03-11 12:01 ` Richard Biener
0 siblings, 1 reply; 2+ messages in thread
From: Alan Lawrence @ 2016-03-11 10:14 UTC (permalink / raw)
To: gcc-patches; +Cc: jamborm
In this PR, a packed structure containing bitfields, loses part of its constant-pool initialization in SRA.
A fuller explanation is on the PR:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70013#c11. In short we need to
treat constant-pool entries, like function parameters, as both come
'pre-initialized' before the function starts.
Bootstrapped + regtest (gcc, g++) on AArch64; same with addition of Ada, on ARM
and x86.
OK for trunk?
gcc/ChangeLog:
PR tree-optimization/70013
* tree-sra.c (analyze_access_subtree): Also set grp_unscalarized_data
for constant-pool entries.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/sra-20.c: New.
---
gcc/testsuite/gcc.dg/tree-ssa/sra-20.c | 20 ++++++++++++++++++++
gcc/tree-sra.c | 3 ++-
2 files changed, 22 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/sra-20.c
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/sra-20.c b/gcc/testsuite/gcc.dg/tree-ssa/sra-20.c
new file mode 100644
index 0000000..5002c24
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/sra-20.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -Wall" } */
+/* PR/70013, SRA of constant-pool loads removes initialization of part of d. */
+#pragma pack (1)
+struct S0 {
+ unsigned f0 : 17;
+};
+
+int c;
+
+int
+main (int argc, char **argv)
+{
+ struct S0 d[] = { { 1 }, { 2 } };
+ struct S0 e = d[1];
+
+ c = d[0].f0;
+ __builtin_printf ("%x\n", e.f0);
+ return 0;
+}
diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index 72157ed..24eac6a 100644
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -2427,7 +2427,8 @@ analyze_access_subtree (struct access *root, struct access *parent,
if (!hole || root->grp_total_scalarization)
root->grp_covered = 1;
- else if (root->grp_write || TREE_CODE (root->base) == PARM_DECL)
+ else if (root->grp_write || TREE_CODE (root->base) == PARM_DECL
+ || constant_decl_p (root->base))
root->grp_unscalarized_data = 1; /* not covered and written to */
return sth_created;
}
--
1.9.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] Fix PR70013
2016-03-11 10:14 [PATCH] Fix PR70013 Alan Lawrence
@ 2016-03-11 12:01 ` Richard Biener
0 siblings, 0 replies; 2+ messages in thread
From: Richard Biener @ 2016-03-11 12:01 UTC (permalink / raw)
To: Alan Lawrence; +Cc: GCC Patches, jamborm
On Fri, Mar 11, 2016 at 11:14 AM, Alan Lawrence <alan.lawrence@arm.com> wrote:
> In this PR, a packed structure containing bitfields, loses part of its constant-pool initialization in SRA.
>
> A fuller explanation is on the PR:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70013#c11. In short we need to
> treat constant-pool entries, like function parameters, as both come
> 'pre-initialized' before the function starts.
>
> Bootstrapped + regtest (gcc, g++) on AArch64; same with addition of Ada, on ARM
> and x86.
>
> OK for trunk?
Ok.
Richard.
> gcc/ChangeLog:
>
> PR tree-optimization/70013
> * tree-sra.c (analyze_access_subtree): Also set grp_unscalarized_data
> for constant-pool entries.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/sra-20.c: New.
> ---
> gcc/testsuite/gcc.dg/tree-ssa/sra-20.c | 20 ++++++++++++++++++++
> gcc/tree-sra.c | 3 ++-
> 2 files changed, 22 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/sra-20.c
>
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/sra-20.c b/gcc/testsuite/gcc.dg/tree-ssa/sra-20.c
> new file mode 100644
> index 0000000..5002c24
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/sra-20.c
> @@ -0,0 +1,20 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -Wall" } */
> +/* PR/70013, SRA of constant-pool loads removes initialization of part of d. */
> +#pragma pack (1)
> +struct S0 {
> + unsigned f0 : 17;
> +};
> +
> +int c;
> +
> +int
> +main (int argc, char **argv)
> +{
> + struct S0 d[] = { { 1 }, { 2 } };
> + struct S0 e = d[1];
> +
> + c = d[0].f0;
> + __builtin_printf ("%x\n", e.f0);
> + return 0;
> +}
> diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
> index 72157ed..24eac6a 100644
> --- a/gcc/tree-sra.c
> +++ b/gcc/tree-sra.c
> @@ -2427,7 +2427,8 @@ analyze_access_subtree (struct access *root, struct access *parent,
>
> if (!hole || root->grp_total_scalarization)
> root->grp_covered = 1;
> - else if (root->grp_write || TREE_CODE (root->base) == PARM_DECL)
> + else if (root->grp_write || TREE_CODE (root->base) == PARM_DECL
> + || constant_decl_p (root->base))
> root->grp_unscalarized_data = 1; /* not covered and written to */
> return sth_created;
> }
> --
> 1.9.1
>
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