* [PATCH V1] HIGH part of symbol ref is invalid for constant pool
@ 2022-07-19 14:30 Jiufu Guo
2022-07-25 10:12 ` Kewen.Lin
2022-07-26 21:36 ` Segher Boessenkool
0 siblings, 2 replies; 5+ messages in thread
From: Jiufu Guo @ 2022-07-19 14:30 UTC (permalink / raw)
To: gcc-patches; +Cc: segher, dje.gcc, linkw, guojiufu
Hi,
In patch https://gcc.gnu.org/pipermail/gcc-patches/2022-July/597712.html,
test case was not added. After more check, a testcase is added for it.
The high part of the symbol address is invalid for the constant pool.
In function rs6000_cannot_force_const_mem, we already return true for
"HIGH with UNSPEC" rtx. Below are some examples also indicate the high
part of a symbol_ref:
(high:DI (const:DI (plus:DI (symbol_ref:DI ("xx") (const_int 12 [0xc])))))
(high:DI (symbol_ref:DI ("var_1")..)))
This patch updates rs6000_cannot_force_const_mem to return true for
rtx with HIGH code.
Bootstrapped and regtested on ppc64le and ppc64.
Is it ok for trunk?
BR,
Jeff(Jiufu)
gcc/ChangeLog:
* config/rs6000/rs6000.cc (rs6000_cannot_force_const_mem):
Return true for HIGH code rtx.
gcc/testsuite/ChangeLog:
* gcc.target/powerpc/constpoolcheck.c: New test.
---
gcc/config/rs6000/rs6000.cc | 7 +++++--
gcc/testsuite/gcc.target/powerpc/constpoolcheck.c | 11 +++++++++++
2 files changed, 16 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 0af2085adc0..d56832ebbfc 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -9704,8 +9704,11 @@ rs6000_init_stack_protect_guard (void)
static bool
rs6000_cannot_force_const_mem (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
{
- if (GET_CODE (x) == HIGH
- && GET_CODE (XEXP (x, 0)) == UNSPEC)
+ /* High part of a symbol ref/address can not be put into constant pool. e.g.
+ (high:DI (symbol_ref:DI ("var")..)) or
+ (high:DI (unspec:DI [(symbol_ref/u:DI ("*.LC0")..)
+ (high:DI (const:DI (plus:DI (symbol_ref:DI ("xx")) (const_int 12)))). */
+ if (GET_CODE (x) == HIGH)
return true;
/* A TLS symbol in the TOC cannot contain a sum. */
diff --git a/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c b/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
new file mode 100644
index 00000000000..ed7a994827b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
@@ -0,0 +1,11 @@
+/* { dg-do compile { target powerpc*-*-* } } */
+/* { dg-options "-O1 -mdejagnu-cpu=power10" } */
+/* (high:DI (symbol_ref:DI ("var_48")..))) should not cause ICE. */
+extern short var_48;
+void
+foo (double *r)
+{
+ if (var_48)
+ *r = 1234.5678;
+}
+
--
2.17.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH V1] HIGH part of symbol ref is invalid for constant pool
2022-07-19 14:30 [PATCH V1] HIGH part of symbol ref is invalid for constant pool Jiufu Guo
@ 2022-07-25 10:12 ` Kewen.Lin
2022-07-26 6:42 ` Jiufu Guo
2022-07-26 21:36 ` Segher Boessenkool
1 sibling, 1 reply; 5+ messages in thread
From: Kewen.Lin @ 2022-07-25 10:12 UTC (permalink / raw)
To: Jiufu Guo; +Cc: segher, dje.gcc, linkw, gcc-patches
Hi Jeff,
on 2022/7/19 22:30, Jiufu Guo wrote:
> Hi,
>
> In patch https://gcc.gnu.org/pipermail/gcc-patches/2022-July/597712.html,
> test case was not added. After more check, a testcase is added for it.
>
Good to see that you constructed one actual test case, nice! :)
> The high part of the symbol address is invalid for the constant pool.
> In function rs6000_cannot_force_const_mem, we already return true for
> "HIGH with UNSPEC" rtx. Below are some examples also indicate the high
> part of a symbol_ref:
> (high:DI (const:DI (plus:DI (symbol_ref:DI ("xx") (const_int 12 [0xc])))))
> (high:DI (symbol_ref:DI ("var_1")..)))
>
> This patch updates rs6000_cannot_force_const_mem to return true for
> rtx with HIGH code.
>
> Bootstrapped and regtested on ppc64le and ppc64.
> Is it ok for trunk?
I think this patch is OK with some nits below tweaked.
>
> BR,
> Jeff(Jiufu)
>
>
> gcc/ChangeLog:
>
> * config/rs6000/rs6000.cc (rs6000_cannot_force_const_mem):
> Return true for HIGH code rtx.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/powerpc/constpoolcheck.c: New test.
>
> ---
> gcc/config/rs6000/rs6000.cc | 7 +++++--
> gcc/testsuite/gcc.target/powerpc/constpoolcheck.c | 11 +++++++++++
> 2 files changed, 16 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
>
> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
> index 0af2085adc0..d56832ebbfc 100644
> --- a/gcc/config/rs6000/rs6000.cc
> +++ b/gcc/config/rs6000/rs6000.cc
> @@ -9704,8 +9704,11 @@ rs6000_init_stack_protect_guard (void)
> static bool
> rs6000_cannot_force_const_mem (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
> {
> - if (GET_CODE (x) == HIGH
> - && GET_CODE (XEXP (x, 0)) == UNSPEC)
> + /* High part of a symbol ref/address can not be put into constant pool. e.g.
Nit: two spaces after the period in "... pool.".
> + (high:DI (symbol_ref:DI ("var")..)) or
Nit: You have one "or" at the end of the above line, I think it's better to
keep the below line consistent by either removing the above " or" or adding
one "or" at the end of the below line.
> + (high:DI (unspec:DI [(symbol_ref/u:DI ("*.LC0")..)
> + (high:DI (const:DI (plus:DI (symbol_ref:DI ("xx")) (const_int 12)))). */
> + if (GET_CODE (x) == HIGH)
> return true;
>
> /* A TLS symbol in the TOC cannot contain a sum. */
> diff --git a/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c b/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
> new file mode 100644
> index 00000000000..ed7a994827b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
Maybe it's good to name it to "const-pool-check.c" or "not-force-const-mem.c".
> @@ -0,0 +1,11 @@
> +/* { dg-do compile { target powerpc*-*-* } } */
Nit: this "dg-do" line isn't needed since all here are default.
BR,
Kewen
> +/* { dg-options "-O1 -mdejagnu-cpu=power10" } */
> +/* (high:DI (symbol_ref:DI ("var_48")..))) should not cause ICE. */
> +extern short var_48;
> +void
> +foo (double *r)
> +{
> + if (var_48)
> + *r = 1234.5678;
> +}
> +
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH V1] HIGH part of symbol ref is invalid for constant pool
2022-07-25 10:12 ` Kewen.Lin
@ 2022-07-26 6:42 ` Jiufu Guo
0 siblings, 0 replies; 5+ messages in thread
From: Jiufu Guo @ 2022-07-26 6:42 UTC (permalink / raw)
To: Kewen.Lin; +Cc: segher, dje.gcc, linkw, gcc-patches
"Kewen.Lin" <linkw@linux.ibm.com> writes:
> Hi Jeff,
>
> on 2022/7/19 22:30, Jiufu Guo wrote:
>> Hi,
>>
>> In patch https://gcc.gnu.org/pipermail/gcc-patches/2022-July/597712.html,
>> test case was not added. After more check, a testcase is added for it.
>>
>
> Good to see that you constructed one actual test case, nice! :)
>
>> The high part of the symbol address is invalid for the constant pool.
>> In function rs6000_cannot_force_const_mem, we already return true for
>> "HIGH with UNSPEC" rtx. Below are some examples also indicate the high
>> part of a symbol_ref:
>> (high:DI (const:DI (plus:DI (symbol_ref:DI ("xx") (const_int 12 [0xc])))))
>> (high:DI (symbol_ref:DI ("var_1")..)))
>>
>> This patch updates rs6000_cannot_force_const_mem to return true for
>> rtx with HIGH code.
>>
>> Bootstrapped and regtested on ppc64le and ppc64.
>> Is it ok for trunk?
>
> I think this patch is OK with some nits below tweaked.
Thanks so much for your time to review and helpful comments!
I will update accordingly before commit.
BR,
Jeff(Jiufu)
>
>>
>> BR,
>> Jeff(Jiufu)
>>
>>
>> gcc/ChangeLog:
>>
>> * config/rs6000/rs6000.cc (rs6000_cannot_force_const_mem):
>> Return true for HIGH code rtx.
>>
>> gcc/testsuite/ChangeLog:
>>
>> * gcc.target/powerpc/constpoolcheck.c: New test.
>>
>> ---
>> gcc/config/rs6000/rs6000.cc | 7 +++++--
>> gcc/testsuite/gcc.target/powerpc/constpoolcheck.c | 11 +++++++++++
>> 2 files changed, 16 insertions(+), 2 deletions(-)
>> create mode 100644 gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
>>
>> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
>> index 0af2085adc0..d56832ebbfc 100644
>> --- a/gcc/config/rs6000/rs6000.cc
>> +++ b/gcc/config/rs6000/rs6000.cc
>> @@ -9704,8 +9704,11 @@ rs6000_init_stack_protect_guard (void)
>> static bool
>> rs6000_cannot_force_const_mem (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
>> {
>> - if (GET_CODE (x) == HIGH
>> - && GET_CODE (XEXP (x, 0)) == UNSPEC)
>> + /* High part of a symbol ref/address can not be put into constant pool. e.g.
>
> Nit: two spaces after the period in "... pool.".
Thanks!
>
>> + (high:DI (symbol_ref:DI ("var")..)) or
>
> Nit: You have one "or" at the end of the above line, I think it's better to
> keep the below line consistent by either removing the above " or" or adding
> one "or" at the end of the below line.
Thanks!
>
>> + (high:DI (unspec:DI [(symbol_ref/u:DI ("*.LC0")..)
>
>
>> + (high:DI (const:DI (plus:DI (symbol_ref:DI ("xx")) (const_int 12)))). */
>> + if (GET_CODE (x) == HIGH)
>> return true;
>>
>> /* A TLS symbol in the TOC cannot contain a sum. */
>> diff --git a/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c b/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
>> new file mode 100644
>> index 00000000000..ed7a994827b
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
>
> Maybe it's good to name it to "const-pool-check.c" or "not-force-const-mem.c".
Great sugguestion! Thanks.
>
>> @@ -0,0 +1,11 @@
>> +/* { dg-do compile { target powerpc*-*-* } } */
>
> Nit: this "dg-do" line isn't needed since all here are default.
Thanks for your comments!
>
> BR,
> Kewen
>
>> +/* { dg-options "-O1 -mdejagnu-cpu=power10" } */
>> +/* (high:DI (symbol_ref:DI ("var_48")..))) should not cause ICE. */
>> +extern short var_48;
>> +void
>> +foo (double *r)
>> +{
>> + if (var_48)
>> + *r = 1234.5678;
>> +}
>> +
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH V1] HIGH part of symbol ref is invalid for constant pool
2022-07-19 14:30 [PATCH V1] HIGH part of symbol ref is invalid for constant pool Jiufu Guo
2022-07-25 10:12 ` Kewen.Lin
@ 2022-07-26 21:36 ` Segher Boessenkool
2022-07-28 12:53 ` Jiufu Guo
1 sibling, 1 reply; 5+ messages in thread
From: Segher Boessenkool @ 2022-07-26 21:36 UTC (permalink / raw)
To: Jiufu Guo; +Cc: gcc-patches, dje.gcc, linkw
Hi!
On Tue, Jul 19, 2022 at 10:30:54PM +0800, Jiufu Guo wrote:
> In patch https://gcc.gnu.org/pipermail/gcc-patches/2022-July/597712.html,
> test case was not added. After more check, a testcase is added for it.
>
> The high part of the symbol address is invalid for the constant pool.
Invalid, how so? Is there a PR related here?
But it is not particularly useful ever, either: we do not know two
different addresses will have the same HIGH unless we know the exact
address, and then we don't need HIGH anyway.
> * config/rs6000/rs6000.cc (rs6000_cannot_force_const_mem):
> Return true for HIGH code rtx.
* config/rs6000/rs6000.cc (rs6000_cannot_force_const_mem): Return true
for HIGH code rtx.
Please don't wrap lines early: changelog lines are 80 positions long,
including the leading tab (which counts as eight positions).
> static bool
> rs6000_cannot_force_const_mem (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
> {
> - if (GET_CODE (x) == HIGH
> - && GET_CODE (XEXP (x, 0)) == UNSPEC)
> + /* High part of a symbol ref/address can not be put into constant pool. e.g.
> + (high:DI (symbol_ref:DI ("var")..)) or
> + (high:DI (unspec:DI [(symbol_ref/u:DI ("*.LC0")..)
> + (high:DI (const:DI (plus:DI (symbol_ref:DI ("xx")) (const_int 12)))). */
> + if (GET_CODE (x) == HIGH)
> return true;
I'm not sure the new comment is helpful at all? Are these examples of
where the compiler (or assembler perhaps) will choke?
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
> @@ -0,0 +1,11 @@
> +/* { dg-do compile { target powerpc*-*-* } } */
Everything in gcc.target/powerpc is target powerpc* always.
> +/* { dg-options "-O1 -mdejagnu-cpu=power10" } */
> +/* (high:DI (symbol_ref:DI ("var_48")..))) should not cause ICE. */
Ah, so there is an ICE, I see. Please open a PR, and mention that in
the testcase as well as in the commit message and changelog.
I agree with what the patch does, it just needs a little more work :-)
Segher
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH V1] HIGH part of symbol ref is invalid for constant pool
2022-07-26 21:36 ` Segher Boessenkool
@ 2022-07-28 12:53 ` Jiufu Guo
0 siblings, 0 replies; 5+ messages in thread
From: Jiufu Guo @ 2022-07-28 12:53 UTC (permalink / raw)
To: Segher Boessenkool; +Cc: gcc-patches, dje.gcc, linkw
Segher Boessenkool <segher@kernel.crashing.org> writes:
Thanks a lot for your review!
> Hi!
>
> On Tue, Jul 19, 2022 at 10:30:54PM +0800, Jiufu Guo wrote:
>> In patch https://gcc.gnu.org/pipermail/gcc-patches/2022-July/597712.html,
>> test case was not added. After more check, a testcase is added for it.
>>
>> The high part of the symbol address is invalid for the constant pool.
>
> Invalid, how so? Is there a PR related here?
Thanks, I just opened PR106460 for this issue.
>
> But it is not particularly useful ever, either: we do not know two
> different addresses will have the same HIGH unless we know the exact
> address, and then we don't need HIGH anyway.
>
>> * config/rs6000/rs6000.cc (rs6000_cannot_force_const_mem):
>> Return true for HIGH code rtx.
>
> * config/rs6000/rs6000.cc (rs6000_cannot_force_const_mem): Return true
> for HIGH code rtx.
>
> Please don't wrap lines early: changelog lines are 80 positions long,
> including the leading tab (which counts as eight positions).
Thanks for your suggestion!
>
>> static bool
>> rs6000_cannot_force_const_mem (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
>> {
>> - if (GET_CODE (x) == HIGH
>> - && GET_CODE (XEXP (x, 0)) == UNSPEC)
>> + /* High part of a symbol ref/address can not be put into constant pool. e.g.
>> + (high:DI (symbol_ref:DI ("var")..)) or
>> + (high:DI (unspec:DI [(symbol_ref/u:DI ("*.LC0")..)
>> + (high:DI (const:DI (plus:DI (symbol_ref:DI ("xx")) (const_int 12)))). */
>> + if (GET_CODE (x) == HIGH)
>> return true;
>
> I'm not sure the new comment is helpful at all? Are these examples of
> where the compiler (or assembler perhaps) will choke?
I debugged this function with the source code from GCC bootstrap and
regtest, and then figured out these examples.
In the next version patch, I updated the comments a little, hope that
is more meaningful. :-)
>
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/constpoolcheck.c
>> @@ -0,0 +1,11 @@
>> +/* { dg-do compile { target powerpc*-*-* } } */
>
> Everything in gcc.target/powerpc is target powerpc* always.
Thanks! I would remove this line.
>
>> +/* { dg-options "-O1 -mdejagnu-cpu=power10" } */
>> +/* (high:DI (symbol_ref:DI ("var_48")..))) should not cause ICE. */
>
> Ah, so there is an ICE, I see. Please open a PR, and mention that in
> the testcase as well as in the commit message and changelog.
Thanks! I should open PR ealry :)
In the updated patch, a testcase is named as pr106460.c, and memtioned
in commit message and changelog.
>
> I agree with what the patch does, it just needs a little more work :-)
I submitted a new version patch:
https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598980.html
Thanks in advance for any comments!
BR,
Jeff(Jiufu)
>
>
> Segher
^ permalink raw reply [flat|nested] 5+ messages in thread
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2022-07-19 14:30 [PATCH V1] HIGH part of symbol ref is invalid for constant pool Jiufu Guo
2022-07-25 10:12 ` Kewen.Lin
2022-07-26 6:42 ` Jiufu Guo
2022-07-26 21:36 ` Segher Boessenkool
2022-07-28 12:53 ` Jiufu Guo
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