[Bug target/15533] Missed move to partial register

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=15533

--- Comment #6 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Cesar Eduardo Barros from comment #0)
> When compiling:
> #include <stdint.h>
> #define regparm __attribute__((regparm(3)))
> uint8_t a;
> uint16_t regparm fn(uint16_t b)
> { return (b & ~0xFF) | a; }

This should probably be optimized in match.pd to BIT_INSERT_EXPR.