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Re: PowerPC64 large toc model
- From: Alan Modra <amodra at gmail dot com>
- To: gcc-patches at gcc dot gnu dot org, David Edelsohn <edelsohn at gnu dot org>
- Date: Fri, 25 Jun 2010 20:13:01 +0930
- Subject: Re: PowerPC64 large toc model
- References: <20100608125703.GI7312@bubble.grove.modra.org>
On Tue, Jun 08, 2010 at 10:27:03PM +0930, Alan Modra wrote:
> -mcmodel=medium
> uses 32-bit toc offsets and addresses static data, string constants
> etc. relative to the toc pointer. Limits data to around 2G.
We now have the mcmodel=medium optimization in the linker, so there
isn't much point in having this in gcc. Patch preapproved by David
and committed after bootstrap and regression testing.
* doc/invoke.texi: Delete mcmodel=medium from powerpc options.
* config/rs6000/rs6000.h (enum rs6000_cmodel): Delete CMODEL_MEDIUM.
* config/rs6000/linux64.h (SUBSUBTARGET_OVERRIDE_OPTIONS): Set
CMODEL_LARGE as default.
* config/rs6000/rs6000.c (rs6000_handle_option): Remove mcmodel=medium.
(offsettable_ok_by_alignment): Delete.
(rs6000_emit_move): Remove mcmodel=medium optimization.
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 161360)
+++ gcc/doc/invoke.texi (working copy)
@@ -14987,11 +14987,6 @@ scheduling parameters set by @option{-mt
Generate PowerPC64 code for the small model: The TOC is limited to
64k.
-@item -mcmodel=medium
-@opindex mcmodel=medium
-Generate PowerPC64 code for the medium model: The TOC and other static
-data may be up to a total of 4G in size.
-
@item -mcmodel=large
@opindex mcmodel=large
Generate PowerPC64 code for the large model: The TOC may be up to 4G
Index: gcc/config/rs6000/linux64.h
===================================================================
--- gcc/config/rs6000/linux64.h (revision 161360)
+++ gcc/config/rs6000/linux64.h (working copy)
@@ -134,7 +134,7 @@ extern enum rs6000_cmodel cmodel;
else \
{ \
if (!rs6000_explicit_options.cmodel) \
- SET_CMODEL (CMODEL_MEDIUM); \
+ SET_CMODEL (CMODEL_LARGE); \
if (cmodel != CMODEL_SMALL) \
{ \
TARGET_NO_FP_IN_TOC = 0; \
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 161360)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -3653,8 +3653,6 @@ rs6000_handle_option (size_t code, const
case OPT_mcmodel_:
if (strcmp (arg, "small") == 0)
cmodel = CMODEL_SMALL;
- else if (strcmp (arg, "medium") == 0)
- cmodel = CMODEL_MEDIUM;
else if (strcmp (arg, "large") == 0)
cmodel = CMODEL_LARGE;
else
@@ -6636,36 +6634,6 @@ rs6000_eliminate_indexed_memrefs (rtx op
copy_addr_to_reg (XEXP (operands[1], 0)));
}
-/* Return true if memory accesses to DECL are known to never straddle
- a 32k boundary. */
-
-static bool
-offsettable_ok_by_alignment (tree decl)
-{
- unsigned HOST_WIDE_INT dsize;
-
- /* Presume any compiler generated symbol_ref is suitably aligned. */
- if (!decl)
- return true;
-
- if (TREE_CODE (decl) != VAR_DECL
- && TREE_CODE (decl) != PARM_DECL
- && TREE_CODE (decl) != RESULT_DECL
- && TREE_CODE (decl) != FIELD_DECL)
- return true;
-
- if (!host_integerp (DECL_SIZE_UNIT (decl), 1))
- return false;
-
- dsize = tree_low_cst (DECL_SIZE_UNIT (decl), 1);
- if (dsize <= 1)
- return true;
- if (dsize > 32768)
- return false;
-
- return DECL_ALIGN_UNIT (decl) >= dsize;
-}
-
/* Emit a move from SOURCE to DEST in mode MODE. */
void
rs6000_emit_move (rtx dest, rtx source, enum machine_mode mode)
@@ -6979,16 +6947,11 @@ rs6000_emit_move (rtx dest, rtx source,
/* If this is a SYMBOL_REF that refers to a constant pool entry,
and we have put it in the TOC, we just need to make a TOC-relative
reference to it. */
- if ((TARGET_TOC
- && GET_CODE (operands[1]) == SYMBOL_REF
- && constant_pool_expr_p (operands[1])
- && ASM_OUTPUT_SPECIAL_POOL_ENTRY_P (get_pool_constant (operands[1]),
- get_pool_mode (operands[1])))
- || (TARGET_CMODEL == CMODEL_MEDIUM
- && GET_CODE (operands[1]) == SYMBOL_REF
- && !CONSTANT_POOL_ADDRESS_P (operands[1])
- && SYMBOL_REF_LOCAL_P (operands[1])
- && offsettable_ok_by_alignment (SYMBOL_REF_DECL (operands[1]))))
+ if (TARGET_TOC
+ && GET_CODE (operands[1]) == SYMBOL_REF
+ && constant_pool_expr_p (operands[1])
+ && ASM_OUTPUT_SPECIAL_POOL_ENTRY_P (get_pool_constant (operands[1]),
+ get_pool_mode (operands[1])))
{
rtx reg = NULL_RTX;
if (TARGET_CMODEL != CMODEL_SMALL)
Index: gcc/config/rs6000/rs6000.h
===================================================================
--- gcc/config/rs6000/rs6000.h (revision 161360)
+++ gcc/config/rs6000/rs6000.h (working copy)
@@ -295,11 +295,9 @@ extern const char *host_detect_local_cpu
/* Code model for 64-bit linux.
small: 16-bit toc offsets.
- medium: 32-bit toc offsets, static data and code within 2G of TOC pointer.
- large: 32-bit toc offsets, no limit on static data and code. */
+ large: 32-bit toc offsets. */
enum rs6000_cmodel {
CMODEL_SMALL,
- CMODEL_MEDIUM,
CMODEL_LARGE
};
--
Alan Modra
Australia Development Lab, IBM