* [PATCH]middle-end: fix epilog reductions when vector iters peeled [PR113364]
@ 2024-01-23 15:40 Tamar Christina
2024-01-23 15:41 ` Richard Biener
0 siblings, 1 reply; 2+ messages in thread
From: Tamar Christina @ 2024-01-23 15:40 UTC (permalink / raw)
To: gcc-patches; +Cc: nd, rguenther, jlaw
[-- Attachment #1: Type: text/plain, Size: 2542 bytes --]
Hi All,
This fixes a bug where vect_create_epilog_for_reduction does not handle the
case where all exits are early exits. In this case we should do like induction
handling code does and not have a main exit.
Bootstrapped Regtested on x86_64-pc-linux-gnu
with --enable-checking=release --enable-lto --with-arch=native
--with-build-config=bootstrap-O3 --enable-checking=yes,rtl,extra.
This shows that some new miscompiles are happening (stage3 is likely miscompiled)
but that's unrelated to this patch and I'll look at it next.
Ok for master?
Thanks,
Tamar
gcc/ChangeLog:
PR tree-optimization/113364
* tree-vect-loop.cc (vect_create_epilog_for_reduction): If all exits all
early exits then we must reduce from the first offset for all of them.
gcc/testsuite/ChangeLog:
PR tree-optimization/113364
* gcc.dg/vect/vect-early-break_107-pr113364.c: New test.
--- inline copy of patch --
diff --git a/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c b/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c
new file mode 100644
index 0000000000000000000000000000000000000000..f489265dbfe5eb8fe302dcc34901abaf6e6d5c14
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-add-options vect_early_break } */
+/* { dg-require-effective-target vect_early_break } */
+/* { dg-require-effective-target vect_int } */
+/* { dg-additional-options "-w" } */
+
+typedef const unsigned char *It;
+It DecodeSLEB128(It begin, It end, int *v) {
+ int value = 0;
+ unsigned shift = 0;
+ unsigned char byte;
+ do
+ {
+ if (begin == end)
+ return begin;
+ byte = *(begin++);
+ int slice = byte & 0x7f;
+ value |= slice << shift;
+ } while (byte >= 128);
+ *v = value;
+ return begin;
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index fe631252dc2258e8ea42179b4ba068a480be9e38..4da1421c8f09746ef4b293573e4f861b642349e1 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -5982,7 +5982,8 @@ vect_create_epilog_for_reduction (loop_vec_info loop_vinfo,
loop-closed PHI of the inner loop which we remember as
def for the reduction PHI generation. */
bool double_reduc = false;
- bool main_exit_p = LOOP_VINFO_IV_EXIT (loop_vinfo) == loop_exit;
+ bool main_exit_p = LOOP_VINFO_IV_EXIT (loop_vinfo) == loop_exit
+ && !LOOP_VINFO_EARLY_BREAKS_VECT_PEELED (loop_vinfo);
stmt_vec_info rdef_info = stmt_info;
if (STMT_VINFO_DEF_TYPE (stmt_info) == vect_double_reduction_def)
{
--
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diff --git a/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c b/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c
new file mode 100644
index 0000000000000000000000000000000000000000..f489265dbfe5eb8fe302dcc34901abaf6e6d5c14
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-add-options vect_early_break } */
+/* { dg-require-effective-target vect_early_break } */
+/* { dg-require-effective-target vect_int } */
+/* { dg-additional-options "-w" } */
+
+typedef const unsigned char *It;
+It DecodeSLEB128(It begin, It end, int *v) {
+ int value = 0;
+ unsigned shift = 0;
+ unsigned char byte;
+ do
+ {
+ if (begin == end)
+ return begin;
+ byte = *(begin++);
+ int slice = byte & 0x7f;
+ value |= slice << shift;
+ } while (byte >= 128);
+ *v = value;
+ return begin;
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index fe631252dc2258e8ea42179b4ba068a480be9e38..4da1421c8f09746ef4b293573e4f861b642349e1 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -5982,7 +5982,8 @@ vect_create_epilog_for_reduction (loop_vec_info loop_vinfo,
loop-closed PHI of the inner loop which we remember as
def for the reduction PHI generation. */
bool double_reduc = false;
- bool main_exit_p = LOOP_VINFO_IV_EXIT (loop_vinfo) == loop_exit;
+ bool main_exit_p = LOOP_VINFO_IV_EXIT (loop_vinfo) == loop_exit
+ && !LOOP_VINFO_EARLY_BREAKS_VECT_PEELED (loop_vinfo);
stmt_vec_info rdef_info = stmt_info;
if (STMT_VINFO_DEF_TYPE (stmt_info) == vect_double_reduction_def)
{
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH]middle-end: fix epilog reductions when vector iters peeled [PR113364]
2024-01-23 15:40 [PATCH]middle-end: fix epilog reductions when vector iters peeled [PR113364] Tamar Christina
@ 2024-01-23 15:41 ` Richard Biener
0 siblings, 0 replies; 2+ messages in thread
From: Richard Biener @ 2024-01-23 15:41 UTC (permalink / raw)
To: Tamar Christina; +Cc: gcc-patches, nd, jlaw
On Tue, 23 Jan 2024, Tamar Christina wrote:
> Hi All,
>
> This fixes a bug where vect_create_epilog_for_reduction does not handle the
> case where all exits are early exits. In this case we should do like induction
> handling code does and not have a main exit.
>
> Bootstrapped Regtested on x86_64-pc-linux-gnu
> with --enable-checking=release --enable-lto --with-arch=native
> --with-build-config=bootstrap-O3 --enable-checking=yes,rtl,extra.
>
> This shows that some new miscompiles are happening (stage3 is likely miscompiled)
> but that's unrelated to this patch and I'll look at it next.
>
> Ok for master?
OK, but can you, as followup, change the name of main_exit_p which
doesn't reflect how it's computed now?
> Thanks,
> Tamar
>
> gcc/ChangeLog:
>
> PR tree-optimization/113364
> * tree-vect-loop.cc (vect_create_epilog_for_reduction): If all exits all
> early exits then we must reduce from the first offset for all of them.
>
> gcc/testsuite/ChangeLog:
>
> PR tree-optimization/113364
> * gcc.dg/vect/vect-early-break_107-pr113364.c: New test.
>
> --- inline copy of patch --
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c b/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..f489265dbfe5eb8fe302dcc34901abaf6e6d5c14
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c
> @@ -0,0 +1,22 @@
> +/* { dg-do compile } */
> +/* { dg-add-options vect_early_break } */
> +/* { dg-require-effective-target vect_early_break } */
> +/* { dg-require-effective-target vect_int } */
> +/* { dg-additional-options "-w" } */
> +
> +typedef const unsigned char *It;
> +It DecodeSLEB128(It begin, It end, int *v) {
> + int value = 0;
> + unsigned shift = 0;
> + unsigned char byte;
> + do
> + {
> + if (begin == end)
> + return begin;
> + byte = *(begin++);
> + int slice = byte & 0x7f;
> + value |= slice << shift;
> + } while (byte >= 128);
> + *v = value;
> + return begin;
> +}
> diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
> index fe631252dc2258e8ea42179b4ba068a480be9e38..4da1421c8f09746ef4b293573e4f861b642349e1 100644
> --- a/gcc/tree-vect-loop.cc
> +++ b/gcc/tree-vect-loop.cc
> @@ -5982,7 +5982,8 @@ vect_create_epilog_for_reduction (loop_vec_info loop_vinfo,
> loop-closed PHI of the inner loop which we remember as
> def for the reduction PHI generation. */
> bool double_reduc = false;
> - bool main_exit_p = LOOP_VINFO_IV_EXIT (loop_vinfo) == loop_exit;
> + bool main_exit_p = LOOP_VINFO_IV_EXIT (loop_vinfo) == loop_exit
> + && !LOOP_VINFO_EARLY_BREAKS_VECT_PEELED (loop_vinfo);
> stmt_vec_info rdef_info = stmt_info;
> if (STMT_VINFO_DEF_TYPE (stmt_info) == vect_double_reduction_def)
> {
>
>
>
>
>
--
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
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2024-01-23 15:41 ` Richard Biener
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