Multiple assignment of C6000 compiler

Masashi Ohhashi

Other Parts Discussed in Thread: TCI6638K2K

My customer uses C6000 compiler(CGTool v7.4.4) for TCI6638K2K. They found a issue about multiple assignment when they had some troubles in their system. Attached text file is extracted from their code. It seems that the assembler code that compiler generated is related to 6.6.1 Single Assignment Programming in TMS320C66x DSP CPU and Instruction Set Reference Guide(SPRUGH7). It is described methods for preventing problems but this issue is generated from compiler. So it is difficult to find the multiple assignment in their program.

1. Is this a compiler bug?

2. Do you have any idea to find multiple assignment that compiler generated or workaround?

Fullscreen asm_code_generated_compiler .txt Download

/* Assmble code generated from C6000 compiler (CGtool v7.4.4) */
/* It is wrong value in ILC (or A5). */ 

   ; PIPED LOOP PROLOG
;          EXCLUSIVE CPU CYCLES: 25

           SHL     .S1     A16,5,A3 
||         MPYLI   .M1X    A4,B6,A5:A4

           MVK     .S1     1000,A31
||         ADD     .L1X    A6,B8,A5 
||         SUBAW   .D1     A3,A16,A3 

           ADD     .L1     A31,A5,A9         ; <-interrupt is happened here

           SHL     .S1     A16,4,A6
||         LDHU    .D1T1   *A9,A5

           MVK     .S1     10000,A4
||         ADD     .L1     A13,A4,A30

           ADDAW   .D1     A6,A16,A29
||         ADD     .L1     A4,A30,A18

           ADD     .L1     A18,A29,A4
           ADD     .D1     A4,28,A4

           SPLOOPD 8       ;24               ; (P) 
||         MVC     .S2X    A5,ILC

Regards,

M.Ohhashi

over 9 years ago

George Mock over 9 years ago

TI__Guru**** 252020 points

That assembly output doesn't look right. To understand what happened, we need to generate this code ourselves. Please preprocess the source file which contains this loop and attach that to your next post. Please mark the loop in the source with comment // PROBLEM LOOP HERE. Also show the build options exactly as the compiler sees them.

Thanks and regards,

-George

Archaeologist over 9 years ago in reply to George Mock

TI__Guru* 84285 points

I agree with George. It does look like there is a bug here, but we'll need a more complete test case for analysis.

Masashi Ohhashi over 9 years ago in reply to Archaeologist

TI__Expert 4805 points

Hi,
Thank you for your reply.

It is difficult for my customer to provide the source code. Because the source code is big and they would like to avoid leaking thier technical information when they provide the source code. So they want to know how to find multiple assignment that compiler generated or workaround. Could you please tell us any suggestion? (it is no proboem like we search the keyword in assembler code.)

Best Regards,
M.Ohhashi

George Mock over 9 years ago in reply to Masashi Ohhashi

TI__Guru**** 252020 points

For those following this thread ... It is continuing on using communication channels within TI. I'll post a summary once everything has settled.

Thanks and regards,

-George

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Multiple assignment of C6000 compiler