Kugan Vivekanandarajah <kugan.vivekanandara...@linaro.org> writes:
> Hi Richard,
>
> On Thu, 6 Jun 2019 at 22:07, Richard Sandiford
> <richard.sandif...@arm.com> wrote:
>>
>> Kugan Vivekanandarajah <kugan.vivekanandara...@linaro.org> writes:
>> > Hi Richard,
>> >
>> > On Thu, 6 Jun 2019 at 19:35, Richard Sandiford
>> > <richard.sandif...@arm.com> wrote:
>> >>
>> >> Kugan Vivekanandarajah <kugan.vivekanandara...@linaro.org> writes:
>> >> > Hi Richard,
>> >> >
>> >> > Thanks for the review. Attached is the latest patch.
>> >> >
>> >> > For testcase like cond_arith_1.c, with the patch, gcc ICE in fwprop. I
>> >> > am limiting fwprop in cases like this. Is there a better fix for this?
>> >> > index cf2c9de..2c99285 100644
>> >> > --- a/gcc/fwprop.c
>> >> > +++ b/gcc/fwprop.c
>> >> > @@ -1358,6 +1358,15 @@ forward_propagate_and_simplify (df_ref use,
>> >> > rtx_insn *def_insn, rtx def_set)
>> >> > else
>> >> > mode = GET_MODE (*loc);
>> >> >
>> >> > + /* TODO. We can't get the mode for
>> >> > + (set (reg:VNx16BI 109)
>> >> > + (unspec:VNx16BI [
>> >> > + (reg:SI 131)
>> >> > + (reg:SI 106)
>> >> > + ] UNSPEC_WHILE_LO))
>> >> > + Thus, bailout when it is UNSPEC and MODEs are not compatible. */
>> >> > + if (GET_MODE_CLASS (mode) != GET_MODE_CLASS (GET_MODE (reg)))
>> >> > + return false;
>> >> > new_rtx = propagate_rtx (*loc, mode, reg, src,
>> >> > optimize_bb_for_speed_p (BLOCK_FOR_INSN (use_insn)));
>> >>
>> >> What specifically goes wrong? The unspec above isn't that unusual --
>> >> many unspecs have different modes from their inputs.
>> >
>> > cond_arith_1.c:38:1: internal compiler error: in paradoxical_subreg_p,
>> > at rtl.h:3130
>> > 0x135f1d3 paradoxical_subreg_p(machine_mode, machine_mode)
>> > ../../88838/gcc/rtl.h:3130
>> > 0x135f1d3 propagate_rtx
>> > ../../88838/gcc/fwprop.c:683
>> > 0x135f4a3 forward_propagate_and_simplify
>> > ../../88838/gcc/fwprop.c:1371
>> > 0x135f4a3 forward_propagate_into
>> > ../../88838/gcc/fwprop.c:1430
>> > 0x135fdcb fwprop
>> > ../../88838/gcc/fwprop.c:1519
>> > 0x135fdcb execute
>> > ../../88838/gcc/fwprop.c:1550
>> > Please submit a full bug report,
>> > with preprocessed source if appropriate.
>> >
>> >
>> > in forward_propagate_and_simplify
>> >
>> > use_set:
>> > (set (reg:VNx16BI 96 [ loop_mask_52 ])
>> > (unspec:VNx16BI [
>> > (reg:SI 92 [ _3 ])
>> > (reg:SI 95 [ niters.36 ])
>> > ] UNSPEC_WHILE_LO))
>> >
>> > reg:
>> > (reg:SI 92 [ _3 ])
>> >
>> > *loc:
>> > (unspec:VNx16BI [
>> > (reg:SI 92 [ _3 ])
>> > (reg:SI 95 [ niters.36 ])
>> > ] UNSPEC_WHILE_LO)
>> >
>> > src:
>> > (subreg:SI (reg:DI 136 [ ivtmp_101 ]) 0)
>> >
>> > use_insn:
>> > (insn 87 86 88 4 (parallel [
>> > (set (reg:VNx16BI 96 [ loop_mask_52 ])
>> > (unspec:VNx16BI [
>> > (reg:SI 92 [ _3 ])
>> > (reg:SI 95 [ niters.36 ])
>> > ] UNSPEC_WHILE_LO))
>> > (clobber (reg:CC 66 cc))
>> > ]) 4255 {while_ultsivnx16bi}
>> > (expr_list:REG_UNUSED (reg:CC 66 cc)
>> > (nil)))
>> >
>> > I think we calculate the mode to be VNx16BI which is wrong?
>> > because of which in propgate_rtx, !paradoxical_subreg_p (mode,
>> > GET_MODE (SUBREG_REG (new_rtx))))) ICE
>>
>> Looks like something I hit on the ACLE branch, but didn't have a
>> non-ACLE reproducer for (see 065881acf0de35ff7818c1fc92769e1c106e1028).
>>
>> Does the attached work? The current call is wrong because "mode"
>> is the mode of "x", not the mode of "new_rtx".
>
> Yes, attached patch works for this testcase. Are you planning to
> commit it to trunk. I will wait for this.
Needs approval first. :-)
The patch was originally bootstrapped & regtested on aarch64-linux-gnu,
but I'll repeat that for trunk and test x86_64-linux-gnu too.
Richard
>
> Thanks,
> Kugan
>>
>> Thanks,
>> Richard
>>
>>
>> 2019-06-06 Richard Sandiford <richard.sandif...@arm.com>
>>
>> gcc/
>> * fwprop.c (propagate_rtx): Fix call to paradoxical_subreg_p.
>>
>> Index: gcc/fwprop.c
>> ===================================================================
>> --- gcc/fwprop.c 2019-03-08 18:14:25.333011645 +0000
>> +++ gcc/fwprop.c 2019-06-06 13:04:34.423476690 +0100
>> @@ -680,7 +680,7 @@ propagate_rtx (rtx x, machine_mode mode,
>> || CONSTANT_P (new_rtx)
>> || (GET_CODE (new_rtx) == SUBREG
>> && REG_P (SUBREG_REG (new_rtx))
>> - && !paradoxical_subreg_p (mode, GET_MODE (SUBREG_REG (new_rtx)))))
>> + && !paradoxical_subreg_p (new_rtx)))
>> flags |= PR_CAN_APPEAR;
>> if (!varying_mem_p (new_rtx))
>> flags |= PR_HANDLE_MEM;
