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Message
From: 'Rask Ingemann Lambertsen'<rask@s...>
Date: Wed Dec 12 15:35:09 CET 2007
Subject: [openrisc] Re: Help with another constraint
On Wed, Dec 12, 2007 at 12:06:04AM -0500, Balaji V. Iyer wrote:
> Hello Everyone,
> I got past that negdi2 and some errors..now I am trying to compile
> some linux module, and it says I am not able to find this constraint:
>
> init/main.c: In function 'start_kernel':
> init/main.c:441: error: insn does not satisfy its constraints:
> (insn 112 110 478 12 (set (mem:QI (reg/v/f:SI 16 r16 [orig:72 line.183 ]
> [72]) [0 S1 A8])
> (const_int 0 [0x0])) 16 {movqi} (nil)
> (nil))
> init/main.c:441: internal compiler error: in
> reload_cse_simplify_operands, at postreload.c:391
> Please submit a full bug report,
>
> Here is what I have for movqi:
The movxx patterns are special and you'll need to hold the compiler's
hands a little. Since your target can't move immediates directly to memory,
you have to ask for a secondary reload to an intermediate register. Use the
target hook TARGET_SECONDARY_RELOAD.
When you've got the secondary reloads working, you can likely improve
code quality:
1) Use a movqi expander to expand the instructions correctly to begin with.
For example, if operand 0 is in memory and operand 1 is an immediate, use
operands[1] = force_reg (QImode, operands[1]);
Rename the "movqi" insn to "*movqi".
> (define_insn "movqi"
> [(set (match_operand:QI 0 "nonimmediate_operand" "=p,q,m,m,p,q,p,q")
> (match_operand:QI 1 "general_operand" "m,m,p,q,p,q,I,I"))]
> ""
^^
2) Reject operand combinations that aren't supported, such as operand 0
being in memory and operand 1 being an immediate.
You can look at other RISC targets (e.g. ARM, PA-RISC, MIPS, SPARC, Alpha
or RS6000) for examples.
> "*
New ports should not use the old-style "* ... " C-blocks. Use { ... } as
documented. Then you'll also avoid the \" and \\ sequences.
> switch(which_alternative)
> {
> case 0:
> case 1:
> return \"l.lbz \\t%0,%1\";
> case 2:
> case 3:
> return \"l.sb \\t%0,%1\";
> case 4:
> case 5:
> return \"l.ori \\t%0,%1,0\\t # move reg to reg\";
> case 6:
> case 7:
> return \"l.addi \\t%0,r0,%1\\t # move immediate\";
> default:
> return \"invalid alternative\";
> }
Presumably you've temporarily coded it this way for debugging purposes.
If not, use the normal way:
"@
l.lbz ...
l.sb ...
..."
> To give a quick explanation:
> p = register numbers between 0-31 (inclusive)
> q = register numbers between 32-63 (inclusive)
You use them in pairs a lot. Define a register class which consists of
registers 0-64 and use that in your constraints.
--
Rask Ingemann Lambertsen
Danish law requires addresses in e-mail to be logged and stored for a year
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