DJ Delorie - Re: [mn10300] return-in-a0-d0 ABI helper (original) (raw)

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• From: DJ Delorie
• To: law at redhat dot com
• Cc: rth at redhat dot com, gcc-patches at gcc dot gnu dot org
• Date: Fri, 16 Sep 2005 16:15:53 -0400
• Subject: Re: [mn10300] return-in-a0-d0 ABI helper
• References: <200509092229.j89MT5OB011869@greed.delorie.com> <20050910003851.GB23773@redhat.com> <200509100051.j8A0pLhh013775@greed.delorie.com> <1126316715.15142.59.camel@localhost.localdomain>

This situation is precisely why we support PARALLELs for return values (the need to return a value in multiple registers).

It ought to "just work".

It just didn't.

../../gcc/gcc/testsuite/gcc.c-torture/compile/20000804-1.c:16: error: unrecognizable insn: (insn 77 90 82 7 (set (parallel/i:SI [ (expr_list:REG_DEP_TRUE (reg:SI 4 a0) (const_int 0 [0x0])) (expr_list:REG_DEP_TRUE (reg:SI 0 d0) (const_int 0 [0x0])) ]) (reg/f:SI 71 [ D.1210 ])) -1 (nil) (nil))

If I manually try all the permutations of caller/callee/int/pointer, they all work, and the code looks reasonable. Relevent portions of the patch attached - see any obvious mistakes in it?

+/* Return the location of the function's value. This will be either

• d0forintegerfunctions,d0 for integer functions, d0forintegerfunctions,a0 for pointers, or a PARALLEL of both
• d0andd0 and d0anda0 if the -mreturn-pointer-on-do flag is set. Note that
• we only return the PARALLEL for outgoing values; we do not want
• callers relying on this extra copy. */
• +rtx +mn10300_function_value (tree valtype, tree func, int outgoing) +{
• rtx rv;
• enum machine_mode mode = TYPE_MODE (valtype);
• if (! POINTER_TYPE_P (valtype))
• return gen_rtx_REG (mode, FIRST_DATA_REGNUM);
• else if (! TARGET_PTR_A0D0 || ! outgoing)
• return gen_rtx_REG (mode, FIRST_ADDRESS_REGNUM);
• rv = gen_rtx_PARALLEL (mode, rtvec_alloc (2));
• XVECEXP (rv, 0, 0)
• = gen_rtx_EXPR_LIST (VOIDmode,

•       gen_rtx_REG (mode, FIRST_ADDRESS_REGNUM),

•       GEN_INT (0));

• XVECEXP (rv, 0, 1)
• = gen_rtx_EXPR_LIST (VOIDmode,

•       gen_rtx_REG (mode, FIRST_DATA_REGNUM),

•       GEN_INT (0));

• return rv; +}

#define FUNCTION_VALUE(VALTYPE, FUNC) \

• gen_rtx_REG (TYPE_MODE (VALTYPE), POINTER_TYPE_P (VALTYPE) \

•       ? FIRST_ADDRESS_REGNUM : FIRST_DATA_REGNUM)

• mn10300_function_value (VALTYPE, FUNC, 0) +#define FUNCTION_OUTGOING_VALUE(VALTYPE, FUNC) \
• mn10300_function_value (VALTYPE, FUNC, 1)

• Follow-Ups:
  • Re: [mn10300] return-in-a0-d0 ABI helper
    * From: Ian Lance Taylor
  • Re: [mn10300] return-in-a0-d0 ABI helper
    * From: Jeffrey A Law
• References:
  • [mn10300] return-in-a0-d0 ABI helper
    * From: DJ Delorie
  • Re: [mn10300] return-in-a0-d0 ABI helper
    * From: Richard Henderson
  • Re: [mn10300] return-in-a0-d0 ABI helper
    * From: DJ Delorie
  • Re: [mn10300] return-in-a0-d0 ABI helper
    * From: Jeffrey A Law