[Bug target/79058] [7 Regression] ARM: internal compiler error: in extract_constrain_insn, at recog.c:2213

[vogt at linux dot vnet.ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79058

--- Comment #14 from Dominik Vogt <vogt at linux dot vnet.ibm.com> ---
Isn't this more or less the same problem as the Avr issue?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78883

On Avr, the register allocator would allow r31:HI if the expression is a
paradoxical subreg of memory.  This results in an invalid register pair,
r31/r32.

On Arm, the register allocator allows r0:SI for (subreg:DI (reg:SI)).  Again we
get an invalid register pair, r-1/r0.  (Note that the cause of the crash is a
"-1" in "regno"; comment 8.)

=> Bug in the register allocator?