Ian Lance Taylor - Re: PATCH COMMITTED: First lower-subreg patch (original) (raw)

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• From: Ian Lance Taylor
• To: "Richard Guenther"
• Cc: "Grigory Zagorodnev" <grigory_zagorodnev at linux dot intel dot com>, gcc-patches at gcc dot gnu dot org
• Date: 01 Feb 2007 08:42:48 -0800
• Subject: Re: PATCH COMMITTED: First lower-subreg patch
• References: <m3mz3yvg9d.fsf@localhost.localdomain> <45C19C01.3080709@linux.intel.com> <m3k5z1ubs1.fsf@localhost.localdomain> <84fc9c000702010751x3f9752e0r8ca24aca41d1491c@mail.gmail.com>

"Richard Guenther" richard.guenther@gmail.com writes:

On 01 Feb 2007 07:40:14 -0800, Ian Lance Taylor iant@google.com wrote:

Grigory Zagorodnev grigory_zagorodnev@linux.intel.com writes:

Ian Lance Taylor wrote:

I am about to commit the first lower-subreg patch. Where possible, gcc/ChangeLog: 2007-01-31 Richard Henderson rth@redhat.com Ian Lance Taylor iant@google.com

Hi, Ian! Unfortunately your patch leads to bootstrap failure at x86_64-redhat-linux. Error log is listed below.

Sorry about that. I only tested on 32-bit systems. Not that I see why this case couldn't arise on a 32-bit system.

I'm currently testing this patch. I don't have an x86_64 bootstrap going at the moment--could you give it a try? Thanks.

It get's me past the failure point, so I suggest to apply it ;)

Makes sense.

Committed without a full test, on the grounds that 1) it should fix a bootstrap problem, and 2) it will only change cases which would have previously ICEd.

Ian

2007-02-01 Ian Lance Taylor iant@google.com

* lower-subreg.c (simplify_gen_subreg_concatn): If we ask for the
high part of a paradoxical subreg, return a constant zero.

Index: lower-subreg.c

--- lower-subreg.c (revision 121461) +++ lower-subreg.c (working copy) @@ -372,6 +372,8 @@ static rtx simplify_gen_subreg_concatn (enum machine_mode outermode, rtx op, enum machine_mode innermode, unsigned int byte) {

• rtx ret;
• /* We have to handle generating a SUBREG of a SUBREG of a CONCATN. If OP is a SUBREG of a CONCATN, then it must be a simple mode change with the same size and offset 0, or it must extract a

@@ -405,9 +407,24 @@ simplify_gen_subreg_concatn (enum machin gcc_assert (op != NULL_RTX); gcc_assert (innermode == GET_MODE (op)); } + if (GET_CODE (op) == CONCATN) return simplify_subreg_concatn (outermode, op, byte);

• return simplify_gen_subreg (outermode, op, innermode, byte);

• ret = simplify_gen_subreg (outermode, op, innermode, byte);
• /* If we see an insn like (set (reg:DI) (subreg:DI (reg:SI) 0)) then

• resolve_simple_move will ask for the high part of the paradoxical

• subreg, which does not have a value.  Just return a zero.  */

• if (ret == NULL_RTX

•  && GET_CODE (op) == SUBREG

•  && SUBREG_BYTE (op) == 0

•  && (GET_MODE_SIZE (innermode)

•  > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op)))))

• return CONST0_RTX (outermode);
• gcc_assert (ret != NULL_RTX);
• return ret; }

/* Return whether we should resolve X into the registers into which it

• References:
  • PATCH COMMITTED: First lower-subreg patch
    * From: Ian Lance Taylor
  • Re: PATCH COMMITTED: First lower-subreg patch
    * From: Grigory Zagorodnev
  • Re: PATCH COMMITTED: First lower-subreg patch
    * From: Ian Lance Taylor
  • Re: PATCH COMMITTED: First lower-subreg patch
    * From: Richard Guenther