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[PATCH/m68k] fix jump table addressing
- From: Roman Zippel <zippel at linux-m68k dot org>
- To: gcc-patches at gcc dot gnu dot org
- Date: Wed, 19 Sep 2007 15:40:11 +0200 (CEST)
- Subject: [PATCH/m68k] fix jump table addressing
Hi,
This removes the workaround for some assemblers to address the jump
table with "Lnnn-LInnn-2.b(%pc)" and simply uses "Lnnn(%pc)" now, this
means the code to generate the extra label can go now.
As a side effect it allows gas to generate the best addressing based on
the offset.
The patch had been previously approved here
http://gcc.gnu.org/ml/gcc-patches/2007-02/msg00407.html
but there were conflicts with the ColdFire patches, so this patch is now
updated and retested.
bye, Roman
200x-xx-xx Roman Zippel <zippel@linux-m68k.org>
* config/m68k/m68k.c (output_move_himode): Remove jump table
recognition.
config/m68k/m68k.md (lea): Likewise.
* config/m68k/m68k.c (print_operand_address): Use simple pc
relative addressing.
---
gcc/config/m68k/m68k.c | 33 ++-------------------------------
gcc/config/m68k/m68k.md | 23 ++---------------------
2 files changed, 4 insertions(+), 52 deletions(-)
Index: gcc/gcc/config/m68k/m68k.c
===================================================================
--- gcc.orig/gcc/config/m68k/m68k.c
+++ gcc/gcc/config/m68k/m68k.c
@@ -2362,25 +2362,6 @@ output_move_himode (rtx *operands)
}
else if (CONSTANT_P (operands[1]))
return "move%.l %1,%0";
- /* Recognize the insn before a tablejump, one that refers
- to a table of offsets. Such an insn will need to refer
- to a label on the insn. So output one. Use the label-number
- of the table of offsets to generate this label. This code,
- and similar code below, assumes that there will be at most one
- reference to each table. */
- if (GET_CODE (operands[1]) == MEM
- && GET_CODE (XEXP (operands[1], 0)) == PLUS
- && GET_CODE (XEXP (XEXP (operands[1], 0), 1)) == LABEL_REF
- && GET_CODE (XEXP (XEXP (operands[1], 0), 0)) != PLUS)
- {
- rtx labelref = XEXP (XEXP (operands[1], 0), 1);
- if (MOTOROLA)
- asm_fprintf (asm_out_file, "\t.set %LLI%d,.+2\n",
- CODE_LABEL_NUMBER (XEXP (labelref, 0)));
- else
- (*targetm.asm_out.internal_label) (asm_out_file, "LI",
- CODE_LABEL_NUMBER (XEXP (labelref, 0)));
- }
return "move%.w %1,%0";
}
@@ -3822,16 +3803,6 @@ print_operand (FILE *file, rtx op, int l
It is possible for PIC to generate a (plus (label_ref...) (reg...))
and we handle that just like we would a (plus (symbol_ref...) (reg...)).
- Some SGS assemblers have a bug such that "Lnnn-LInnn-2.b(pc,d0.l*2)"
- fails to assemble. Luckily "Lnnn(pc,d0.l*2)" produces the results
- we want. This difference can be accommodated by using an assembler
- define such "LDnnn" to be either "Lnnn-LInnn-2.b", "Lnnn", or any other
- string, as necessary. This is accomplished via the ASM_OUTPUT_CASE_END
- macro. See m68k/sgs.h for an example; for versions without the bug.
- Some assemblers refuse all the above solutions. The workaround is to
- emit "K(pc,d0.l*2)" with K being a small constant known to give the
- right behavior.
-
They also do not like things like "pea 1.w", so we simple leave off
the .w on small constants.
@@ -3905,7 +3876,7 @@ print_operand_address (FILE *file, rtx a
{
/* Print the "offset(base" component. */
if (labelno >= 0)
- asm_fprintf (file, "%LL%d-%LLI%d.b(%Rpc,", labelno, labelno);
+ asm_fprintf (file, "%LL%d(%Rpc,", labelno);
else
{
if (address.offset)
@@ -3943,7 +3914,7 @@ print_operand_address (FILE *file, rtx a
{
/* Print the "base@(offset" component. */
if (labelno >= 0)
- asm_fprintf (file, "%Rpc@(%LL%d-%LLI%d-2:b", labelno, labelno);
+ asm_fprintf (file, "%Rpc@(%LL%d", labelno);
else
{
if (address.base)
Index: gcc/gcc/config/m68k/m68k.md
===================================================================
--- gcc.orig/gcc/config/m68k/m68k.md
+++ gcc/gcc/config/m68k/m68k.md
@@ -7297,30 +7297,11 @@
;; This should not be used unless the add/sub insns can't be.
-(define_insn ""
+(define_insn "*lea"
[(set (match_operand:SI 0 "nonimmediate_operand" "=a")
(match_operand:QI 1 "address_operand" "p"))]
""
-{
- /* Recognize an insn that refers to a table of offsets. Such an insn will
- need to refer to a label on the insn. So output one. Use the
- label-number of the table of offsets to generate this label. This code,
- and similar code above, assumes that there will be at most one reference
- to each table. */
- if (GET_CODE (operands[1]) == PLUS
- && GET_CODE (XEXP (operands[1], 1)) == LABEL_REF
- && GET_CODE (XEXP (operands[1], 0)) != PLUS)
- {
- rtx labelref = XEXP (operands[1], 1);
- if (MOTOROLA)
- asm_fprintf (asm_out_file, "\\t.set %LLI%d,.+2\\n",
- CODE_LABEL_NUMBER (XEXP (labelref, 0)));
- else
- (*targetm.asm_out.internal_label) (asm_out_file, "LI",
- CODE_LABEL_NUMBER (XEXP (labelref, 0)));
- }
- return "lea %a1,%0";
-})
+ "lea %a1,%0")
;; This is the first machine-dependent peephole optimization.
;; It is useful when a floating value is returned from a function call