https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79058
Andreas Krebbel <krebbel at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |krebbel at gcc dot gnu.org
--- Comment #10 from Andreas Krebbel <krebbel at gcc dot gnu.org> ---
(In reply to Segher Boessenkool from comment #9)
> With the code and flags in comment 2 i get a segmentation fault, instead
> (with a powerpc64-linux host), somewhere during LRA.
>
>
> insn 10 is
> ===
> (insn 10 8 11 2 (set (reg:DI 120)
> (and:DI (subreg:DI (reg:SI 117) 0)
> (const_int 1 [0x1]))) "79058.c":7 79 {*anddi3_insn}
> (expr_list:REG_DEAD (reg:SI 117)
> (nil)))
> ===
>
> and IRA has chosen r0 for both regs (note they are different modes though!)
>
>
> LRA does:
> ===
> Choosing alt 4 in insn 10: (0) &r (1) 0 (2) De {*anddi3_insn}
> Creating newreg=123 from oldreg=120, assigning class GENERAL_REGS to
> r123
> 10: r123:DI=r123:DI&0x1
> REG_DEAD r117:SI
> Inserting insn reload before:
> 17: r123:DI=r117:SI#0
> Inserting insn reload after:
> 18: r120:DI=r123:DI
> ===
>
> r123 is assigned r0 as well, and insn 18 is deleted, and it dies shortly
> after that.
The target operand is marked early clobber. So picking the same reg for both
operands does not appear to be valid to me.
