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Content-Language: en-US To: Jeff Law , Ajit Agarwal , gcc-patches Cc: Segher Boessenkool , Richard Biener , Raphael Zinsly References: <4c0b6b4f-bbc1-8dd0-a91c-ffed028b4873@linux.ibm.com> <365cfb50-4313-d44e-6ffc-77473b20c670@linux.ibm.com> <5834b0cb-dd25-c55f-2cf6-9aa6b8372724@linux.ibm.com> <29ab8ff7-20d5-183f-a0ce-c82758488b64@linux.ibm.com> <1a482ac5-404b-0787-c682-b10d13dc76ee@gmail.com> <247f5af3-5db3-4a73-b636-95e006a3a649@linux.ibm.com> From: Peter Bergner In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: M-lKhDKWUlVIcq7NlqFoB67_DJvVpO46 X-Proofpoint-ORIG-GUID: 9DPkzdudtAao6krODxqvBlNt2QHMokVX X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-24_11,2023-03-24_01,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 bulkscore=0 suspectscore=0 mlxscore=0 mlxlogscore=999 lowpriorityscore=0 clxscore=1011 impostorscore=0 malwarescore=0 priorityscore=1501 phishscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2303200000 definitions=main-2303240164 X-Spam-Status: No, score=-3.6 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 3/23/23 6:12 PM, Jeff Law via Gcc-patches wrote: >>>> Is there a reason why REE cannot see that our (reg:QI 4) is a param register >>>> and thus due to our ABI, already correctly sign/zero extended? >>> >>> I don't think REE has ever considered exploiting ABI constraints. Handling >>> that might be a notable improvement on various targets. It'd be a great >>> place to do some experimentation. >> >> Ok, so sounds like a good follow-on project after this patch is reviewed >> and committed (stage1). Thanks for your input! > > Agreed. I suspect that risc-v will benefit from such work as well. > With that in mind, if y'all start poking at this, please loop in Raphael > (on cc) who's expressed an interest in this space. Will do. I suspect that it'll be best to come up with some generic interface using target hooks like "param regs are sign/zero extended" or "call return values are sign/zero extended", etc. that targets can conditionally opt into depending on their ABI that is in effect. Peter