On 11/19/20 8:36 PM, Maciej W. Rozycki wrote:
> It makes no sense for insn operand predicates, as long as they accept a
> register operand, to be more restrictive than the set of the associated
> constraints, because expand will choose the insn based on the relevant
> operand being a pseudo register then and reload will keep it happily as
> an immediate if a constraint permits it. So the restriction posed by
> such a predicate will be happily ignored, and moreover if a splitter is
> added, such as required for MODE_CC support, the new instructions will
> reject the original operands supplied, causing an ICE like below:
>
> .../gcc/testsuite/gfortran.dg/graphite/PR67518.f90:44:0: Error: could not
> split insn
> (insn 90 662 663 (set (reg:DI 10 %r10 [orig:97 _235 ] [97])
> (mult:DI (sign_extend:DI (mem/c:SI (plus:SI (reg/f:SI 13 %fp)
> (const_int -800 [0xfffffffffffffce0])) [14 %sfp+-800
> S4 A32]))
> (sign_extend:DI (const_int -51 [0xffffffffffffffcd])))) 299
> {mulsidi3}
> (expr_list:REG_EQUAL (mult:DI (sign_extend:DI (subreg:SI (mem/c:DI
> (plus:SI (reg/f:SI 13 %fp)
> (const_int -800 [0xfffffffffffffce0])) [14
> %sfp+-800 S8 A32]) 0))
> (const_int -51 [0xffffffffffffffcd]))
> (nil)))
> during RTL pass: final
> .../gcc/testsuite/gfortran.dg/graphite/PR67518.f90:44:0: internal compiler
> error: in final_scan_insn_1, at final.c:3073
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See <https://gcc.gnu.org/bugs/> for instructions.
>
> Change the predicates used with the widening multiply and multiply-add
> insns to allow immediates then, just as the constraints and the machine
> instructions produced permit.
>
> Also give the insns names, for easier reference here and elsewhere.
>
> gcc/
> * config/vax/vax.md (mulsidi3): Fix the multiplicand predicates.
> (*maddsidi4, *maddsidi4_const): Likewise. Name insns.
OK
jeff
ps. Yes, I skipped the insv/extv changes. They're usually a rats nest
of special cases. We'll come back to them.
