Hi!
On 2022-12-02T12:24:58+0100, I wrote:
> On 2022-03-22T14:41:46+0100, Tom de Vries via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
>> Starting with ptx isa version 6.3, a ptx directive .alias is available.
>> Use this directive to support symbol aliases, as far as possible.
>>
>> The alias support is off by default. It can be turned on using a switch
>> -malias.
>> This patch causes a regression:
>> ...
>> -PASS: gcc.dg/pr60797.c (test for errors, line 4)
>> +FAIL: gcc.dg/pr60797.c (test for errors, line 4)
>> ...
>> The test-case is skipped for effective target alias, and both without and
>> with
>> this patch the nvptx target is considered to not support it, so the
>> test-case is
>> executed. The test-case expects an error message along the lines of "alias
>> definitions not supported in this configuration", but instead we run into:
>> ...
>> gcc.dg/pr60797.c:4:12: error: foo aliased to undefined symbol
>> ...
>> This is probably due to the fact that the nvptx backend now defines macros
>> ASM_OUTPUT_DEF and ASM_OUTPUT_DEF_FROM_DECLS, so from the point of view of
>> the
>> common part of the compiler, aliases are supported.
>
> Testing this with the new '-malias' flag not active (default), I'm seeing
> a number of more regressions:
>
> [...]: error: alias definitions not supported in this configuration
>
> [-PASS:-]{+FAIL:+} gcc.dg/pr56727-1.c (test for excess errors)
>
> PASS: gcc.dg/pr84739.c (test for warnings, line 6)
> PASS: gcc.dg/pr84739.c (test for warnings, line 21)
> [-PASS:-]{+FAIL:+} gcc.dg/pr84739.c (test for excess errors)
>
> [-PASS:-]{+FAIL:+} gcc.dg/ipa/pr81520.c (test for excess errors)
>
> ..., and then, in particular, a ton of regressions in GCC/C++ testing
> ('check-gcc-c++') due to approximately 40000 new
> "error: alias definitions not supported in this configuration"
> diagnostics. Whoops... (I suppose you've not tested that at all?)
>
> If the new '-malias' flag is not active, we have to maintain (restore)
> the previous state of other macros, as I'm demonstrating in the attached
> "[WIP] nvptx 'TARGET_USE_LOCAL_THUNK_ALIAS_P', 'TARGET_SUPPORTS_ALIASES'".
> This completely addresses in particular the 'check-gcc-c++' regressions,
> and does not cause any changes if the new '-malias' flag in fact is
> active (as when testing with '-mptx=6.3 -malias', for example).
>
> However, this further regresses the 'gcc.dg/pr56727-1.c' and
> 'gcc.dg/ipa/pr81520.c' test cases mentioned above:
>
> during IPA pass: whole-program
> [...]: internal compiler error: in function_and_variable_visibility, at
> ipa-visibility.cc:647
>
> {+FAIL: gcc.dg/pr56727-1.c (internal compiler error: in
> function_and_variable_visibility, at ipa-visibility.cc:647)+}
> FAIL: gcc.dg/pr56727-1.c (test for excess errors)
>
> {+FAIL: gcc.dg/ipa/pr81520.c (internal compiler error: in
> function_and_variable_visibility, at ipa-visibility.cc:647)+}
> FAIL: gcc.dg/ipa/pr81520.c (test for excess errors)
>
> Such ICEs we're not yet currently seeing elsewhere; this remains to be
> analyzed -- after all, these test cases PASSed originally.
That'll be addressed by
<https://inbox.sourceware.org/87ledgzxcl....@euler.schwinge.homeip.net>
"More '#ifdef ASM_OUTPUT_DEF' -> 'if (TARGET_SUPPORTS_ALIASES)' etc.":
[-FAIL: gcc.dg/pr56727-1.c (internal compiler error: in
function_and_variable_visibility, at ipa-visibility.cc:647)-]
[-FAIL:-]{+PASS:+} gcc.dg/pr56727-1.c (test for excess errors)
[-FAIL:-]{+PASS:+} gcc.dg/pr60797.c (test for errors, line 4)
[-FAIL:-]{+PASS:+} gcc.dg/pr60797.c (test for excess errors)
[-FAIL: gcc.dg/ipa/pr81520.c (internal compiler error: in
function_and_variable_visibility, at ipa-visibility.cc:647)-]
[-FAIL:-]{+PASS:+} gcc.dg/ipa/pr81520.c (test for excess errors)
> And, obviously, the patch needs some "copy editing".
> --- a/gcc/config/nvptx/nvptx.h
> +++ b/gcc/config/nvptx/nvptx.h
> @@ -338,6 +338,12 @@ struct GTY(()) machine_function
> #define ASM_OUTPUT_DEF_FROM_DECLS(STREAM, NAME, VALUE) \
> nvptx_asm_output_def_from_decls (STREAM, NAME, VALUE)
>
> +//TODO
> +/* ..., but don't let that dummy ASM_OUTPUT_DEF definition influence other
> + macros. */
> +#define TARGET_USE_LOCAL_THUNK_ALIAS_P(DECL) (!((nvptx_alias == 0 ||
> !TARGET_PTX_6_3)))
> +#define TARGET_SUPPORTS_ALIASES (!((nvptx_alias == 0 || !TARGET_PTX_6_3)))
Pushed to master branch commit 537e2cc30d0f8ba6433af52f2fef038d75d93174
"nvptx 'TARGET_USE_LOCAL_THUNK_ALIAS_P', 'TARGET_SUPPORTS_ALIASES'", see
attached.
Grüße
Thomas
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>From 537e2cc30d0f8ba6433af52f2fef038d75d93174 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <tho...@codesourcery.com>
Date: Thu, 14 Jul 2022 22:05:17 +0200
Subject: [PATCH] nvptx 'TARGET_USE_LOCAL_THUNK_ALIAS_P',
'TARGET_SUPPORTS_ALIASES'
This fixes up commit f8b15e177155960017ac0c5daef8780d1127f91c
"[nvptx] Use .alias directive for mptx >= 6.3", which regressed in
particular C++ test cases if the new '-malias' flag was not active.
In that case, we have to maintain (that is now, restore) the previous
state of 'TARGET_USE_LOCAL_THUNK_ALIAS_P', 'TARGET_SUPPORTS_ALIASES'.
The remaining three regressions are to be resolved via
<https://inbox.sourceware.org/87ledgzxcl....@euler.schwinge.homeip.net>
"More '#ifdef ASM_OUTPUT_DEF' -> 'if (TARGET_SUPPORTS_ALIASES)' etc.".
gcc/
* config/nvptx/nvptx.h (TARGET_USE_LOCAL_THUNK_ALIAS_P)
(TARGET_SUPPORTS_ALIASES): Define.
---
gcc/config/nvptx/nvptx.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
index 15a52344d4a..129427e5654 100644
--- a/gcc/config/nvptx/nvptx.h
+++ b/gcc/config/nvptx/nvptx.h
@@ -338,6 +338,11 @@ struct GTY(()) machine_function
#define ASM_OUTPUT_DEF_FROM_DECLS(STREAM, NAME, VALUE) \
nvptx_asm_output_def_from_decls (STREAM, NAME, VALUE)
+/* ..., but also override other macros to avoid 'gcc/defaults.h'-initialization
+ due to that dummy 'ASM_OUTPUT_DEF'. */
+#define TARGET_USE_LOCAL_THUNK_ALIAS_P(DECL) TARGET_SUPPORTS_ALIASES
+#define TARGET_SUPPORTS_ALIASES (nvptx_alias != 0)
+
#define NO_DOT_IN_LABEL
#define ASM_COMMENT_START "//"
--
2.34.1
