[PING][Patch, ARM] cleanup prologue_use pattern

[Richard Earnshaw]

On 17/10/12 11:08, Greta Yorsh wrote:
> Ping!
>

I've been pondering why this was being asked for.  As far as I can tell 
it's just a naming issue (mention of the epilogue in the prologue).

The right thing to do is to rename the pattern to reflect the dual use 
rather than add additional patterns with identical NOP behaviour.  Can't 
you just rename the existing pattern?  Something like "force_register_use"?

R.

> Thanks,
> Greta
>
> -----Original Message-----
> From: Greta Yorsh [mailto:greta.yorsh@arm.com]
> Sent: 10 October 2012 16:14
> To: GCC Patches
> Cc: Ramana Radhakrishnan; Richard Earnshaw; nickc@redhat.com;
> paul@codesourcery.com
> Subject: [Patch, ARM] cleanup prologue_use pattern
>
> The pattern prologue_use is emitted for both prologue and epilogue.
> In particular, the assembly comment
> "@sp needed for prologue"
> is printed out for both prologue and epilogue.
>
> This patch adds a separate pattern for epilogue_use and replaces
> prologue_use with epilogue_use where appropriate.
>
> No regression on qemu for arm-none-eabi.
>
> Ok for trunk?
>
> Thanks,
> Greta
>
> 2012-09-17  Greta Yorsh  <Greta.Yorsh@arm.com>
>
>          * config/arm/arm.md (UNSPEC_EPILOGUE_USE): New unspec value.
>          (sibcall_epilogue): Use UNSPEC_EPILOGUE_USE instead of
>          UNSPEC_PROLOGUE_USE.
>          (epilogue_use): New define_insn.
>          (epilogue): Use gen_epilogue_use instead of gen_prologue_use.
>          * config/arm/arm.c (arm_expand_epilogue): Likewise.
>          (thumb1_expand_epilogue) Likewise.
>
>
> rename-prolog-use.v2.patch.txt
>
>
> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> index dd073da..f23c2d0 100644
> --- a/gcc/config/arm/arm.c
> +++ b/gcc/config/arm/arm.c
> @@ -22581,7 +22581,7 @@ thumb1_expand_epilogue (void)
>
>     /* Emit a USE (stack_pointer_rtx), so that
>        the stack adjustment will not be deleted.  */
> -  emit_insn (gen_prologue_use (stack_pointer_rtx));
> +  emit_insn (gen_epilogue_use (stack_pointer_rtx));
>
>     if (crtl->profile || !TARGET_SCHED_PROLOG)
>       emit_insn (gen_blockage ());
> @@ -22805,7 +22805,7 @@ arm_expand_epilogue (bool really_return)
>
>             /* Emit USE(stack_pointer_rtx) to ensure that stack adjustment is not
>                deleted.  */
> -          emit_insn (gen_prologue_use (stack_pointer_rtx));
> +          emit_insn (gen_epilogue_use (stack_pointer_rtx));
>           }
>         else
>           {
> @@ -22823,7 +22823,7 @@ arm_expand_epilogue (bool really_return)
>             emit_insn (gen_movsi (stack_pointer_rtx, hard_frame_pointer_rtx));
>             /* Emit USE(stack_pointer_rtx) to ensure that stack adjustment is not
>                deleted.  */
> -          emit_insn (gen_prologue_use (stack_pointer_rtx));
> +          emit_insn (gen_epilogue_use (stack_pointer_rtx));
>           }
>       }
>     else
> @@ -22841,7 +22841,7 @@ arm_expand_epilogue (bool really_return)
>                                    GEN_INT (amount)));
>             /* Emit USE(stack_pointer_rtx) to ensure that stack adjustment is
>                not deleted.  */
> -          emit_insn (gen_prologue_use (stack_pointer_rtx));
> +          emit_insn (gen_epilogue_use (stack_pointer_rtx));
>           }
>       }
>
> diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
> index a60e659..6a910a3 100644
> --- a/gcc/config/arm/arm.md
> +++ b/gcc/config/arm/arm.md
> @@ -81,6 +81,7 @@
>                           ; instructions setting registers for EH handling
>                           ; and stack frame generation.  Operand 0 is the
>                           ; register to "use".
> +  UNSPEC_EPILOGUE_USE   ; Same for epilogue.
>     UNSPEC_CHECK_ARCH     ; Set CCs to indicate 26-bit or 32-bit mode.
>     UNSPEC_WSHUFH         ; Used by the intrinsic form of the iWMMXt WSHUFH instruction.
>     UNSPEC_WACC           ; Used by the intrinsic form of the iWMMXt WACC instruction.
> @@ -10610,7 +10611,7 @@
>     "TARGET_EITHER"
>     "
>     if (crtl->calls_eh_return)
> -    emit_insn (gen_prologue_use (gen_rtx_REG (Pmode, 2)));
> +    emit_insn (gen_epilogue_use (gen_rtx_REG (Pmode, 2)));
>     if (TARGET_THUMB1)
>      {
>        thumb1_expand_epilogue ();
> @@ -10644,7 +10645,7 @@
>   ;; does not think that it is unused by the sibcall branch that
>   ;; will replace the standard function epilogue.
>   (define_expand "sibcall_epilogue"
> -   [(parallel [(unspec:SI [(reg:SI LR_REGNUM)] UNSPEC_PROLOGUE_USE)
> +   [(parallel [(unspec:SI [(reg:SI LR_REGNUM)] UNSPEC_EPILOGUE_USE)
>                  (unspec_volatile [(return)] VUNSPEC_EPILOGUE)])]
>      "TARGET_32BIT"
>      "
> @@ -11267,6 +11268,12 @@
>     [(set_attr "length" "0")]
>   )
>
> +(define_insn "epilogue_use"
> +  [(unspec:SI [(match_operand:SI 0 "register_operand" "")] UNSPEC_EPILOGUE_USE)]
> +  ""
> +  "%@ %0 needed for epilogue"
> +  [(set_attr "length" "0")]
> +)
>
>   ;; Patterns for exception handling
>
>