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Paradoxical subreg reload issue
- From: Aurelien Buhrig <aurelien dot buhrig dot gcc at gmail dot com>
- To: gcc at gcc dot gnu dot org
- Date: Wed, 02 May 2012 14:48:42 +0200
- Subject: Paradoxical subreg reload issue
I have an issue (gcc 4.6.3, private bacakend) when reloading operands of
(set (subreg:SI (reg:QI 21 [ iftmp.1 ]) 0)
(lshiftrt:SI (reg/v:SI 24 [ w ]) (const_int 31 [0x1f]))
The register 21 is reloaded into
(reg:QI 0 r0 [orig:21 iftmp.1 ] ), which is a HI-wide hw register.
Since it is a BIG_ENDIAN target, the SI subreg regno is then -1.
Note that word_mode is SImode, whereas the class r0 belongs to is
HI-wide. I don't know if this matters when reloading.
I have no idea how to debug this, if it is a backend or a reload bug.
Thank you in advance,