[Bug target/18404] New: unnecessary sll when -mint64

[Bug target/18404] New: unnecessary sll when -mint64

[fshvaige at cisco dot com]

Configured with:
--target=mips-elf --program-suffix=.mips --with-newlib --without-headers
--enable-languages=c,c++,objc -v

Thread model: single
gcc version 3.4.2

File /tmp/gcctest_01.c:

typedef signed char t_SI __attribute__ ((__mode__(SI)));

t_SI inc_SI (t_SI v) {
    return ++v;
}

Command line:
gcc.mips -S -O2 -march=sb1 -mabi=64 -o /tmp/gcctest_01.s /tmp/gcctest_01.c

Result file gcctest_01.s:

        .file   1 "gcctest_01.c"
        .section .mdebug.abi64
        .previous
        .text
        .align  2
        .align  3
        .globl  inc_SI
        .ent    inc_SI
inc_SI:
        .frame  $sp,0,$31               # vars= 0, regs= 0/0, args= 0, gp= 0
        .mask   0x00000000,0
        .fmask  0x00000000,0
        .set    noreorder
        .set    nomacro
        j       $31
        addiu   $2,$4,1
        .set    macro
        .set    reorder

        .end    inc_SI

Command line:
gcc.mips -S -O2 -march=sb1 -mabi=64 -mint64 -o /tmp/gcctest_01.s /tmp/gcctest_01.c

Result file gcctest_01.s:

        .file   1 "gcctest_01.c"
        .section .mdebug.abi64
        .previous
        .text
        .align  2
        .align  3
        .globl  inc_SI
        .ent    inc_SI
inc_SI:
        .frame  $sp,0,$31               # vars= 0, regs= 0/0, args= 0, gp= 0
        .mask   0x00000000,0
        .fmask  0x00000000,0
        sll     $2,$4,0
        .set    noreorder
        .set    nomacro
        j       $31
        addiu   $2,$2,1
        .set    macro
        .set    reorder

        .end    inc_SI

Question: what is this "sll $2,$4,0" good for or why it absent in first result
(without -mint64) ?

-- 
           Summary: unnecessary sll when -mint64
           Product: gcc
           Version: 3.4.2
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: fshvaige at cisco dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: mips-unknown-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18404

[Bug target/18404] unnecessary sll when -mint64 (MIPS)

[fshvaige at cisco dot com]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|unnecessary sll when -mint64|unnecessary sll when -mint64
                   |                            |(MIPS)


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18404

[Bug target/18404] unnecessary sll when -mint64 (MIPS)

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-11-12 03:34 -------
Note we reject the code as we consider SI mode not able to emulate  with -mint64. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18404

[Bug target/18404] unnecessary sll when -mint64 (MIPS)

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-11-12 03:55 -------
I filed PR 18442 for that regression.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |18442


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18404

[Bug target/18404] unnecessary sll when -mint64 (MIPS)

[echristo at redhat dot com]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2004-12-01 20:02:16
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18404

[Bug target/18404] unnecessary sll when -mint64 (MIPS)

[echristo at redhat dot com]

-- 
Bug 18404 depends on bug 18442, which changed state.

Bug 18442 Summary: [4.0 Regression] Rejects attribute((mode(SI))) when using -mint64
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18442

           What    |Old Value                   |New Value
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18404

[Bug target/18404] unnecessary sll when -mint64 (MIPS)

[echristo at redhat dot com]

------- Additional Comments From echristo at redhat dot com  2005-01-13 02:38 -------
-mint64 is being deprecated in 4.0 and will be removed after branching. What are
you using it for anyhow?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18404

[Bug target/18404] unnecessary sll when -mint64 (MIPS)

[fshvaige at cisco dot com]

------- Additional Comments From fshvaige at cisco dot com  2005-01-18 09:57 -------
Where can I read the discussion preceding this decision ?

Int is default type in C. I want (as option) default to be 64 bit; it seems to
me so natural for 64 bit architecture. I know that 64 bit MIPS CPUs complete
some 32 bit operations faster then corresponding 64 bit ops, but still.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18404

[Bug target/18404] unnecessary sll when -mint64 (MIPS)

[echristo at redhat dot com]

------- Additional Comments From echristo at redhat dot com  2005-01-20 00:37 -------
The discussion was held offline between Richard Sandiford and I. 

Having a -mint64 option changes the abi for anything that is built with that
option and in no abi defined for mips is int defined to 64. You may want longs
equal to 64-bit which I can easily understand, especially for 64-bit
architectures. Pointers can also be 64-bit under the n64 abi (-mabi=64).

As far as 64-bit ints being "natural", in fact, only the unicosmk abi for alpha
(not the rest of the port) defines the size of an integer to 64-bit or allows it.

-eric

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18404

[Bug target/18404] unnecessary sll when -mint64 (MIPS)

[echristo at redhat dot com]

------- Additional Comments From echristo at redhat dot com  2005-02-01 03:06 -------
Deprecating -mint64.

http://gcc.gnu.org/ml/gcc-patches/2005-02/msg00019.html

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|                            |WONTFIX


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18404