On 14/10/13 08:27, Yvan Roux wrote:
> Hi,
>
> The status of LRA support for AArch32 is the sequel :
> - there is some regressions in the testsuite (gcc/g++, libstdc++ and
> fortran) in ARM mode, all due to the same neon legitimate address
> issue (tested in hard and softfp mode).
> - the compiler doesn't bootstrap with LRA enable for thumb (during
> libgcc build).
>
> As stage 1 will be close soon, my first question is can we add the
> code to enable LRA before its ending, and fix the issues during stage
> 2 (according to Vladimir the legitimate address issue is mainly an LRA
> bugfix). The attached patch enables LRA by default but disable it for
> Thumb and let the opportunity to force LRA with -mlra, but maybe we
> can just turn it off by default.
>
> I need your help for the Thumb issue, as suggested by Vladimir I
> disabled secondary reload for thumb (with the attached arm.h.diff
> patch) to let LRA deal with it and break a cycle, but I now face an
> issue exhibited by the attached testcase (thumb-lra.i) and the command
> line:
>
> cc1 -O2 -mthumb -mlra thumb-lra.i
>
> Here LRA as to deal with the thumb1_movhi_insn :
>
> (insn 11 5 14 2 (set (reg:HI 0 r0)
> (const_int -1318 [0xfffffffffffffada])) /work/tmp/t2.i:14 206
> {*thumb1_movhi_insn}
> (nil))
>
> and creates new regs to do it :
>
> 11: r0:HI=r114:HI
> Inserting insn reload before:
> 18: r115:SI=0xfffffffffffffada
> 19: r114:HI=r115:SI#0
> REG_EQUAL 0xfffffffffffffada
>
> Choosing alt 6 in insn 18: (0) l (1) mi {*thumb1_movsi_insn}
> Creating newreg=116 from oldreg=115, assigning class LO_REGS to r116
>
> 18: r116:SI=0xfffffffffffffada
> Inserting insn reload after:
> 20: r115:SI=r116:SI
>
> Creating newreg=117, assigning class LO_REGS to scratch r117
>
> and during this mov processing, we call gen_thumb_movhi_clobber which
> ICE because the first rtx parameter is not a strict memory address but
> a register, and here I'm not sure of what to do between fixing this in
> the backend or in LRA, and how to do it.
>
> Thanks,
> Yvan=
>
>
I'd go with defaulting to LRA off until the regression has been
resolved. You also need a ChangeLog entry.
OK with those done.
R.
