Fwd: Yet another fix for mcore-sim

[Andrew Burgess]

Jeff Law <jeffreyalaw@gmail.com> writes:

> Someday I'll type "sourceware.org" correctly on a consistent basis.
>
>
>
> -------- Forwarded Message --------
> Subject: Yet another fix for mcore-sim
> Date: Sat, 16 Dec 2023 21:52:12 -0700
> From: Jeff Law <jeffreyalaw@gmail.com>
> To: gdb-patches@sourcware.org
>
>
> This came up testing the CRC optimization work from Mariam@RAU. 
> Basically to optimize some CRC loops into table lookups or carryless 
> multiplies, we may need to do a bit reflection, which on the mcore 
> processor is done using a rotate instruction.
>
> Unfortunately the simulator implementation of rotates has the exact same 
> problem as we saw with right shifts.  The input value may have been sign 
> extended from 32 to 64 bits.  When we rotate the extended value, we get 
> those sign extension bits and thus the wrong result.
>
> The fix is the same.  Rather than using a "long", use a uint32_t for the 
> type of the temporary.  This fixes a handful of tests in the GCC testsuite:
>
>> mcore-sim: gcc.c-torture/execute/20100805-1.c   -O0  execution test
>> mcore-sim: gcc.c-torture/execute/20100805-1.c   -O1  execution test
>> mcore-sim: gcc.c-torture/execute/20100805-1.c   -O2  execution test
>> mcore-sim: gcc.c-torture/execute/20100805-1.c   -O2 -flto -fno-use-linker-plugin -flto-partition=none  execution test
>> mcore-sim: gcc.c-torture/execute/20100805-1.c   -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects  execution test
>> mcore-sim: gcc.c-torture/execute/20100805-1.c   -O3 -g  execution test
>> mcore-sim: gcc.c-torture/execute/20100805-1.c   -Os  execution test
>> mcore-sim: gcc.c-torture/execute/20180112-1.c   -O0  execution test
>> mcore-sim: gcc.c-torture/execute/20180112-1.c   -O1  execution test
>> mcore-sim: gcc.c-torture/execute/20180112-1.c   -O2  execution test
>> mcore-sim: gcc.c-torture/execute/20180112-1.c   -O2 -flto -fno-use-linker-plugin -flto-partition=none  execution test
>> mcore-sim: gcc.c-torture/execute/20180112-1.c   -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects  execution test
>> mcore-sim: gcc.c-torture/execute/20180112-1.c   -O3 -g  execution test
>> mcore-sim: gcc.c-torture/execute/20180112-1.c   -Os  execution test
>> mcore-sim: gcc.dg/20050922-1.c execution test
>> mcore-sim: gcc.dg/crc-25.c execution test
>> mcore-sim: gcc.dg/crc-26.c execution test
>> mcore-sim: gcc.dg/crc-8.c execution test
>> mcore-sim: gcc.dg/pr57233.c execution test
>
>
> The crc-* tests are Mariam's CRC optimizer tests.  The rest are 
> regression tests already in the GCC testsuite.
>
> OK for the trunk?

It would be nice if there were some tests added to the simulator tree.
Could you create one similar to sim/testsuite/mcore/lsr.s maybe?

(Pre-)Approved with a test:

Approved-By: Andrew Burgess <aburgess@redhat.com>

Thanks,
Andrew

>
> Jeff
> diff --git a/sim/mcore/interp.c b/sim/mcore/interp.c
> index 8bfb745a11f..94e0a1675be 100644
> --- a/sim/mcore/interp.c
> +++ b/sim/mcore/interp.c
> @@ -1015,7 +1015,7 @@ step_once (SIM_DESC sd, SIM_CPU *cpu)
>  	case 0x38: case 0x39:				/* xsr, rotli */
>  	  {
>  	    unsigned imm = IMM5;
> -	    unsigned long tmp = gr[RD];
> +	    uint32_t tmp = gr[RD];
>  	    if (imm == 0)
>  	      {
>  		int32_t cbit;