[Bug target/66822] New: Turn off X86_TUNE_ZERO_EXTEND_WITH_AND for IAMCU

[Bug target/66822] New: Turn off X86_TUNE_ZERO_EXTEND_WITH_AND for IAMCU

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66822

            Bug ID: 66822
           Summary: Turn off X86_TUNE_ZERO_EXTEND_WITH_AND for IAMCU
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
                CC: julia.koval at intel dot com
  Target Milestone: ---

Since X86_TUNE_ZERO_EXTEND_WITH_AND generates bigger code, should
it be turned off for IAMCU?

[Bug target/66822] Turn off X86_TUNE_ZERO_EXTEND_WITH_AND for -miamcu

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66822

Yulia Koval <julia.koval at intel dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |izamyatin at gmail dot com

--- Comment #1 from Yulia Koval <julia.koval at intel dot com> ---
I think it's a good idea.

[Bug target/66822] Turn off X86_TUNE_ZERO_EXTEND_WITH_AND for -miamcu

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66822

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Yulia Koval from comment #1)
> I think it's a good idea.

If we do that, we may also adjust iamcu_cost:

  COSTS_N_INSNS (3),                    /* cost of movsx */
  COSTS_N_INSNS (2),                    /* cost of movzx */

[Bug target/66822] Turn off X86_TUNE_ZERO_EXTEND_WITH_AND for -miamcu

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66822

--- Comment #3 from Uroš Bizjak <ubizjak at gmail dot com> ---
Please hold a bit with this change, I have a patch that improves generation of
zero_extend substantially.
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Subject: [Bug target/66821] reassoc-37.c fails on -march=iamcu
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idf821

--- Comment #10 from hjl at gcc dot gnu.org <hjl at gcc dot gnu.org> ---
Author: hjl
Date: Thu Jul  9 20:35:56 2015
New Revision: 225635

URL: https://gcc.gnu.org/viewcvs?rev"5635&root=gcc&view=rev
Log:
Adjust variable shift costs for IA MCU

We reduce code size for IA MCU by adjusting variable shift costs for IA
MCU

        PR target/66821
        * config/i386/i386.c (iamcu_cost): Adjust variable shift costs.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/i386.c

[Bug target/66822] Turn -mtune=iamcu for size

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66822

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Turn off                    |Turn -mtune=iamcu for size
                   |X86_TUNE_ZERO_EXTEND_WITH_A |
                   |ND for -miamcu              |

--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> ---
-mtune=iamcu should be tuned for size. X86_TUNE_ZERO_EXTEND_WITH_AND
lead to bigger size:

[hjl@gnu-tools-1 pr66822]$ cat x.i
unsigned int
foo (unsigned short x)
{
  return x;
}
[hjl@gnu-tools-1 pr66822]$ /export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2 -m32 -miamcu -mtune=iamcu
-c -o x.o x.i -mtune-ctrl=^zero_extend_with_and
[hjl@gnu-tools-1 pr66822]$ objdump -dwr x.o

x.o:     file format elf32-i386


Disassembly of section .text:

00000000 <foo>:
   0:   0f b7 c0                movzwl %ax,%eax
   3:   c3                      ret    
[hjl@gnu-tools-1 pr66822]$ /export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2 -m32 -miamcu -mtune=iamcu
-c -o x.o x.i -mtune-ctrl=zero_extend_with_and
[hjl@gnu-tools-1 pr66822]$ objdump -dwr x.o

x.o:     file format elf32-i386


Disassembly of section .text:

00000000 <foo>:
   0:   25 ff ff 00 00          and    $0xffff,%eax
   5:   c3                      ret    
[hjl@gnu-tools-1 pr66822]$

[Bug target/66822] Turn -mtune=iamcu for size

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66822

--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> ---
X86_TUNE_USE_BT also reduces code size:

[hjl@gnu-tools-1 pr66822]$ cat y.i
void bar (void);

void
foo (int x)
{
  if (x != 2 && x != 3 && x != 10 && x != 11 && x != 17 && x != 18 && x != 23)
    bar ();
}
[hjl@gnu-tools-1 pr66822]$ make y.o
/export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2 -m32 -miamcu -mtune=iamcu
-S -o y.s y.i
/export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2 -m32 -miamcu -mtune=iamcu
-c -o y.o y.s
rm y.s
[hjl@gnu-tools-1 pr66822]$ objdump -dwr y.o

y.o:     file format elf32-i386


Disassembly of section .text:

00000000 <foo>:
   0:   83 f8 17                cmp    $0x17,%eax
   3:   76 0b                   jbe    10 <foo+0x10>
   5:   e9 fc ff ff ff          jmp    6 <foo+0x6>      6: R_386_PC32   bar
   a:   8d b6 00 00 00 00       lea    0x0(%esi),%esi
  10:   ba 0c 0c 86 00          mov    $0x860c0c,%edx
  15:   88 c1                   mov    %al,%cl
  17:   d3 ea                   shr    %cl,%edx
  19:   83 e2 01                and    $0x1,%edx
  1c:   74 e7                   je     5 <foo+0x5>
  1e:   c3                      ret    
[hjl@gnu-tools-1 pr66822]$ /export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2 -m32 -miamcu -mtune=iamcu
-c y.i -mtune-ctrl=use_bt
[hjl@gnu-tools-1 pr66822]$ objdump -dwr y.o

y.o:     file format elf32-i386


Disassembly of section .text:

00000000 <foo>:
   0:   83 f8 17                cmp    $0x17,%eax
   3:   76 0b                   jbe    10 <foo+0x10>
   5:   e9 fc ff ff ff          jmp    6 <foo+0x6>      6: R_386_PC32   bar
   a:   8d b6 00 00 00 00       lea    0x0(%esi),%esi
  10:   ba 0c 0c 86 00          mov    $0x860c0c,%edx
  15:   0f a3 c2                bt     %eax,%edx
  18:   73 eb                   jae    5 <foo+0x5>
  1a:   c3                      ret    
[hjl@gnu-tools-1 pr66822]$

[Bug target/66822] Turn -mtune=iamcu for size

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66822

--- Comment #6 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to H.J. Lu from comment #5)
> X86_TUNE_USE_BT also reduces code size:
> 
> [hjl@gnu-tools-1 pr66822]$ cat y.i
> void bar (void);
> 
> void
> foo (int x)
> {
>   if (x != 2 && x != 3 && x != 10 && x != 11 && x != 17 && x != 18 && x !=
> 23)
>     bar ();
> }
> [hjl@gnu-tools-1 pr66822]$ make y.o
> /export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
> -B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2 -m32 -miamcu
> -mtune=iamcu -S -o y.s y.i
> /export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
> -B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2 -m32 -miamcu
> -mtune=iamcu -c -o y.o y.s
> rm y.s
> [hjl@gnu-tools-1 pr66822]$ objdump -dwr y.o
> 
> y.o:     file format elf32-i386
> 
> 
> Disassembly of section .text:
> 
> 00000000 <foo>:
>    0:	83 f8 17             	cmp    $0x17,%eax
>    3:	76 0b                	jbe    10 <foo+0x10>
>    5:	e9 fc ff ff ff       	jmp    6 <foo+0x6>	6: R_386_PC32	bar
>    a:	8d b6 00 00 00 00    	lea    0x0(%esi),%esi
>   10:	ba 0c 0c 86 00       	mov    $0x860c0c,%edx
>   15:	88 c1                	mov    %al,%cl
>   17:	d3 ea                	shr    %cl,%edx
>   19:	83 e2 01             	and    $0x1,%edx
>   1c:	74 e7                	je     5 <foo+0x5>
>   1e:	c3                   	ret    
> [hjl@gnu-tools-1 pr66822]$ /export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
> -B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2 -m32 -miamcu
> -mtune=iamcu -c y.i -mtune-ctrl=use_bt
> [hjl@gnu-tools-1 pr66822]$ objdump -dwr y.o
> 
> y.o:     file format elf32-i386
> 
> 
> Disassembly of section .text:
> 
> 00000000 <foo>:
>    0:	83 f8 17             	cmp    $0x17,%eax
>    3:	76 0b                	jbe    10 <foo+0x10>
>    5:	e9 fc ff ff ff       	jmp    6 <foo+0x6>	6: R_386_PC32	bar
>    a:	8d b6 00 00 00 00    	lea    0x0(%esi),%esi
>   10:	ba 0c 0c 86 00       	mov    $0x860c0c,%edx
>   15:	0f a3 c2             	bt     %eax,%edx
>   18:	73 eb                	jae    5 <foo+0x5>
>   1a:	c3                   	ret    
> [hjl@gnu-tools-1 pr66822]$

We can reduce size further by

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index bca1fee..4f08d0a 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -2556,7 +2556,7 @@ static const struct ptt
processor_target_table[PROCESSOR_max] =
   {"i386", &i386_cost, 4, 3, 4, 3, 4},
   {"i486", &i486_cost, 16, 15, 16, 15, 16},
   {"pentium", &pentium_cost, 16, 7, 16, 7, 16},
-  {"iamcu", &iamcu_cost, 16, 7, 16, 7, 16},
+  {"iamcu", &iamcu_cost, 0, 0, 0, 0, 0},
   {"pentiumpro", &pentiumpro_cost, 16, 15, 16, 10, 16},
   {"pentium4", &pentium4_cost, 0, 0, 0, 0, 0},
   {"nocona", &nocona_cost, 0, 0, 0, 0, 0},

and get

00000000 <foo>:
   0:   83 f8 17                cmp    $0x17,%eax
   3:   76 05                   jbe    a <foo+0xa>
   5:   e9 fc ff ff ff          jmp    6 <foo+0x6>      6: R_386_PC32   bar
   a:   ba 0c 0c 86 00          mov    $0x860c0c,%edx
   f:   0f a3 c2                bt     %eax,%edx
  12:   73 f1                   jae    5 <foo+0x5>
  14:   c3                      ret    
[hjl@gnu-tools-1 pr66822]$
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Subject: [Bug c++/66092] [c++-concepts] Concept can't check variadic template arguments
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idf092

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-07-10
                 CC|                            |jason at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> ---
(In reply to Andrew Sutton from comment #2)
> I think that this should be ill-formed.
>
> template <typename T, typename U, typename... Args>
>   concept bool Same()
>   {
>     return decltype(check<T, U, Args...>())::value;
>   }
>
> template <typename... Args>
> requires Same<Args...>()
>   void foo( Args... args ) {}
>
>
> Template constraint processing requires that flatten (inline) the check for
> Same<Args...>(), but I don't see how we can substitute a dependent argument
> pack into three distinct template parameters (T, U, and ...Args).
>
> The wording prohibiting this is missing in the TS.

Agreed, this is basically the same issue as core issue 1430 for alias
templates.  We can fix the crash on this testcase by adding concepts to the DR
1430 check in coerce_template_parms, but complain is tf_none at that point so
we don't get a helpful error message.  Any thoughts on that?  It seems to me
that we probably want to pass complain through the normalize/lift functions.

Is there something to address this in your latest draft?

[Bug target/66822] Turn -mtune=iamcu for size

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66822

--- Comment #7 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Uroš Bizjak from comment #3)
> Please hold a bit with this change, I have a patch that improves generation
> of zero_extend substantially.

Eh, it won't have such drastic effect on code size, so if size is priority,
X86_TUNE_ZERO_EXTEND_WITH_AND should be disabled.
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Subject: [Bug c++/65592] internal compiler error: Segmentation fault when using non-existent enum class enumerator
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ide592

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> ---
This issue is already fixed in mainline. I'm adding a testcase and closing it.