Hi Richard, I updated this patch using your suggestions. I'm having a problem though, that I'm having trouble nailing. Building libstdc++ for microMIPS is failing trying to generate dwarf2 CFI info:
_Unwind_Ptr base_of_encoded_value(unsigned char, _Unwind_Context*)
Analyzing compilation unit
Performing interprocedural optimizations
<*free_lang_data> <visibility> <early_local_cleanups> <*free_inline_summary>
<whole-program> <profile_estimate> <cp> <inline> <pure-const>
<static-var>Assembling functions:
_Unwind_Ptr base_of_encoded_value(unsigned char, _Unwind_Context*)
mm.cc: In function '_Unwind_Ptr base_of_encoded_value(unsigned char,
_Unwind_Context*)':
mm.cc:34:1: internal compiler error: in maybe_record_trace_start, at
dwarf2cfi.c:2209
0x8570656 maybe_record_trace_start
/scratch/cmoore/umips-elf/src/gcc-4.7-2012.09/gcc/dwarf2cfi.c:2209
0x857113f create_trace_edges
/scratch/cmoore/umips-elf/src/gcc-4.7-2012.09/gcc/dwarf2cfi.c:2301
0x8572505 scan_trace
/scratch/cmoore/umips-elf/src/gcc-4.7-2012.09/gcc/dwarf2cfi.c:2514
0x85726b3 create_cfi_notes
/scratch/cmoore/umips-elf/src/gcc-4.7-2012.09/gcc/dwarf2cfi.c:2540
0x8572703 execute_dwarf2_frame
/scratch/cmoore/umips-elf/src/gcc-4.7-2012.09/gcc/dwarf2cfi.c:2897
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://support.codesourcery.com/GNUToolchain/> for instructions.
I've attached a testcase hoping that you might have some ideas. I plan to
keep debugging in the meanwhile. I was able to reproduce with ./cc1plus
-mmicromips -Os mm.ii.
Thanks,
Catherine
> -----Original Message-----
> From: Richard Sandiford [mailto:rdsandif...@googlemail.com]
> Sent: Tuesday, March 05, 2013 4:10 PM
> To: Moore, Catherine
> Cc: gcc-patches@gcc.gnu.org; Rozycki, Maciej
> Subject: Re: [Patch] Add microMIPS jraddiusp support
>
> "Moore, Catherine" <catherine_mo...@mentor.com> writes:
> > Index: config/mips/micromips.md
> >
> ==========================================================
> =========
> > --- config/mips/micromips.md (revision 196341)
> > +++ config/mips/micromips.md (working copy)
> > @@ -95,6 +95,19 @@
> > (set_attr "mode" "SI")
> > (set_attr "can_delay" "no")])
> >
> > +;; For JRADDIUSP.
> > +(define_insn "jraddiusp"
> > + [(parallel [(return)
> > + (use (reg:SI 31))
> > + (set (reg:SI 29)
> > + (plus:SI (reg:SI 29)
> > + (match_operand 0 "const_int_operand")))])]
>
> Since this is a generic pattern (not depending on UNSPECs, etc.), I think we
> should use a specific predicate instead of const_int_operand.
> From the suggestion in the thread about addition, this would be a "uw5", i.e.
> uw5_operand.
>
> > Index: config/mips/mips.c
> >
> ==========================================================
> =========
> > --- config/mips/mips.c (revision 196341)
> > +++ config/mips/mips.c (working copy)
> > @@ -11364,6 +11364,7 @@
> > const struct mips_frame_info *frame;
> > HOST_WIDE_INT step1, step2;
> > rtx base, adjust, insn;
> > + bool use_jraddiusp_p = false;
> >
> > if (!sibcall_p && mips_can_use_return_insn ())
> > {
> > @@ -11453,6 +11454,14 @@
> > mips_for_each_saved_gpr_and_fpr (frame->total_size - step2,
> > mips_restore_reg);
> >
> > + /* Check if we can use JRADDIUSP. */
> > + use_jraddiusp_p = (TARGET_MICROMIPS
> > + && !crtl->calls_eh_return
> > + && !sibcall_p
> > + && step2 > 0
> > + && (step2 & 3) == 0
> > + && step2 <= (31 << 2));
> > +
> > if (cfun->machine->interrupt_handler_p)
> > {
> > HOST_WIDE_INT offset;
> > @@ -11480,8 +11489,9 @@
> > mips_emit_move (gen_rtx_REG (word_mode, K0_REG_NUM),
> mem);
> > offset -= UNITS_PER_WORD;
> >
> > - /* If we don't use shadow register set, we need to update SP. */
> > - if (!cfun->machine->use_shadow_register_set_p)
> > + /* If we don't use shadow register set or the microMIPS
> > + JRADDIUSP insn, we need to update SP. */
> > + if (!cfun->machine->use_shadow_register_set_p &&
> !use_jraddiusp_p)
> > mips_deallocate_stack (stack_pointer_rtx, GEN_INT (step2), 0);
> > else
> > /* The choice of position is somewhat arbitrary in this case.
> > */
>
> We shouldn't use JRADDIUSP in an interrupt handler, so I think it would be
> better to move the use_jraddiusp_p condition into the else branch and drop
> the hunk above.
>
> > @@ -11492,11 +11502,14 @@
> > gen_rtx_REG (SImode, K0_REG_NUM)));
> > }
> > else
> > - /* Deallocate the final bit of the frame. */
> > - mips_deallocate_stack (stack_pointer_rtx, GEN_INT (step2), 0);
> > + /* Deallocate the final bit of the frame unless using the microMIPS
> > + JRADDIUSP insn. */
> > + if (!use_jraddiusp_p)
> > + mips_deallocate_stack (stack_pointer_rtx, GEN_INT (step2), 0);
> > }
> >
> > - gcc_assert (!mips_epilogue.cfa_restores);
> > + if (!use_jraddiusp_p)
> > + gcc_assert (!mips_epilogue.cfa_restores);
>
> We still need to emit the CFA restores somewhere. Something like:
>
> else if (TARGET_MICROMIPS
> && !crtl->calls_eh_return
> && !sibcall_p
> && step2 > 0
> && mips_unsigned_immediate_p (step2, 5, 2))
> {
> /* We can deallocate the stack and jump to $31 using JRADDIUSP.
> Emit the CFA restores immediately before the deallocation. */
> use_jraddisup_p = true;
> mips_epilogue_emit_cfa_restores ();
> }
> else
> /* Deallocate the final bit of the frame. */
> mips_deallocate_stack (stack_pointer_rtx, GEN_INT (step2), 0);
>
> where mips_unsigned_immediate_p comes from the other thread.
>
> Thanks,
> Richard
jraddiusp.patch
Description: jraddiusp.patch
jraddiusp.cl
Description: jraddiusp.cl
mm.ii
Description: mm.ii
mm.ii.240r.nothrow
Description: mm.ii.240r.nothrow
