Re: Different addressing modes for loads and stores?

Re: Different addressing modes for loads and stores?

[Ulrich Weigand]

Fred Cook wrote:

>My loads support base+offset and base+register addressing while stores
>only have base+offset addressing. My GO_IF_LEGITIMATE_ADDRESS macro
>accepts both addressing modes. Now the question is how to prevent that
>the base+register mode is used for stores. For that changed the movsi
>pattern to:
[snip]
>and I used the EXTRA_CONSTRAINT macro to accept only base+offset
>if the letter argument is 'S'. However, this does not lead to what
>I wanted to achieve. "=r,Sm" or "=r,mS" also does not work.

We've had similar problems on s390 with different addressing modes.
To fix this, I've added the EXTRA_MEMORY_CONSTRAINT feature; this
should do what you want ...


Mit freundlichen Gruessen / Best Regards

Ulrich Weigand

--
  Dr. Ulrich Weigand
  Linux for S/390 Design & Development
  IBM Deutschland Entwicklung GmbH, Schoenaicher Str. 220, 71032 Boeblingen
  Phone: +49-7031/16-3727   ---   Email: Ulrich.Weigand@de.ibm.com

Different addressing modes for loads and stores?

[Fred Cook]

Hi,

How to deal with load and store instructions that have different addressing
modes? This is not unusual so there must be a solution. What I did is
specifying the following pattern in the .md file for word loads and
stores:

(define_insn "movsi"
   [(set (match_operand:SI 0 "nonimmediate_operand" "=r,m")
         (match_operand:SI 1 "general_operand" "m,r"))]
   ""
   "@
   load %1 -> %0
   store %0 %1"
)

My loads support base+offset and base+register addressing while stores
only have base+offset addressing. My GO_IF_LEGITIMATE_ADDRESS macro
accepts both addressing modes. Now the question is how to prevent that
the base+register mode is used for stores. For that changed the movsi
pattern to:

(define_insn "movsi"
   [(set (match_operand:SI 0 "nonimmediate_operand" "=r,S")
         (match_operand:SI 1 "general_operand" "m,r"))]
   ""
   "@
   load %1 -> %0
   store %0 %1"
)

and I used the EXTRA_CONSTRAINT macro to accept only base+offset
if the letter argument is 'S'. However, this does not lead to what
I wanted to achieve. "=r,Sm" or "=r,mS" also does not work.

Any idea how to solve this problem?

Thanks,

Fred.

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