Re: [RFA] New pass for sign/zero extension elimination

[Jeff Law <jlaw@ventanamicro.com>]

On 11/19/23 20:32, Xi Ruoyao wrote:
> On Sun, 2023-11-19 at 19:52 -0700, Jeff Law wrote:
> 
> /* snip */
> 
>>
>>> Unfortunately, I get some ICE building stage 1 libgcc with this patch on
>>> loongarch64-linux-gnu:
>>>
>>> during RTL pass: ext_dce
>>> ../../../gcc/libgcc/libgcc2.c: In function ‘__absvdi2’:
>>> ../../../gcc/libgcc/libgcc2.c:224:1: internal compiler error: Segmentation fault
>>>     224 | }
>>>         | ^
>>> 0x120baa477 crash_signal
>>> 	../../gcc/gcc/toplev.cc:316
>>> 0x1216aeeb4 ext_dce_process_sets
>>> 	../../gcc/gcc/ext-dce.cc:128
>>> 0x1216afbaf ext_dce_process_bb
>>> 	../../gcc/gcc/ext-dce.cc:647
>>> 0x1216afbaf ext_dce
>>> 	../../gcc/gcc/ext-dce.cc:802
>>> 0x1216afbaf execute
>>> 	../../gcc/gcc/ext-dce.cc:868
>>> Please submit a full bug report, with preprocessed source (by using -freport-bug).
>>> Please include the complete backtrace with any bug report.
>>> See <https://gcc.gnu.org/bugs/> for instructions.
>> I think I know what's going on here.
> 
> The gzip-compressed preprocessed file attached, in case you still need
> it.
Thanks.  I'll double check with it in a bit.   Basically there was a 
late cleanup that could result in walking down the wrong part of a chunk 
of RTL.  My tester is about 30-60 minutes from being able to start a run 
with the fix.

Jeff