Revised patch to address conservative behavior in redundant extend
elimination that was resulting in redundant extends not being
removed. Now uses a new target hook machine_mode_from_attr_mode
which is currently enabled only for i386.
Bootstrapped and tested on x86_64-unknown-linux-gnu. Is this ok for trunk?
Thanks,
Teresa
2012-10-11 Teresa Johnson <tejohn...@google.com>
* doc/tm.texi: Document TARGET_MACHINE_MODE_FROM_ATTR_MODE.
* doc/tm.texi.in: Regenerated.
* targhooks.c (default_machine_mode_from_attr_mode): New function.
* targhooks.h (default_machine_mode_from_attr_mode): Declare.
* target.def (machine_mode_from_attr_mode): New target hook.
* ree.c (get_mode): New function.
(add_removable_extension): Use get_mode to obtain the
machine mode for comparison with other extends.
* config/i386/i386.c (ix86_machine_mode_from_attr_mode): New function.
Index: doc/tm.texi
===================================================================
--- doc/tm.texi (revision 192265)
+++ doc/tm.texi (working copy)
@@ -10468,6 +10468,10 @@ In order to enforce the representation of @code{mo
@code{mode}.
@end deftypefn
+@deftypefn {Target Hook} {enum machine_mode}
TARGET_MACHINE_MODE_FROM_ATTR_MODE (rtx @var{insn})
+If @var{insn} has an attr_mode that is equivalent to a @code{machine_mode},
return the corresponding @code{machine_mode}, otherwise return
@code{MAX_MACHINE_MODE}.
+@end deftypefn
+
@defmac STORE_FLAG_VALUE
A C expression describing the value returned by a comparison operator
with an integral mode and stored by a store-flag instruction
Index: doc/tm.texi.in
===================================================================
--- doc/tm.texi.in (revision 192265)
+++ doc/tm.texi.in (working copy)
@@ -10326,6 +10326,8 @@ In order to enforce the representation of @code{mo
@code{mode}.
@end deftypefn
+@hook TARGET_MACHINE_MODE_FROM_ATTR_MODE
+
@defmac STORE_FLAG_VALUE
A C expression describing the value returned by a comparison operator
with an integral mode and stored by a store-flag instruction
Index: targhooks.c
===================================================================
--- targhooks.c (revision 192265)
+++ targhooks.c (working copy)
@@ -250,6 +250,14 @@ default_mode_rep_extended (enum machine_mode mode
return UNKNOWN;
}
+/* The default implementation of TARGET_MACHINE_MODE_FROM_ATTR_MODE. */
+
+enum machine_mode
+default_machine_mode_from_attr_mode (rtx insn ATTRIBUTE_UNUSED)
+{
+ return MAX_MACHINE_MODE;
+}
+
/* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true. */
bool
Index: targhooks.h
===================================================================
--- targhooks.h (revision 192265)
+++ targhooks.h (working copy)
@@ -47,6 +47,7 @@ extern unsigned HOST_WIDE_INT default_shift_trunca
(enum machine_mode);
extern unsigned int default_min_divisions_for_recip_mul (enum machine_mode);
extern int default_mode_rep_extended (enum machine_mode, enum machine_mode);
+enum machine_mode default_machine_mode_from_attr_mode (rtx insn);
extern tree default_stack_protect_guard (void);
extern tree default_external_stack_protect_fail (void);
Index: target.def
===================================================================
--- target.def (revision 192265)
+++ target.def (working copy)
@@ -1576,6 +1576,17 @@ DEFHOOK
int, (enum machine_mode mode, enum machine_mode rep_mode),
default_mode_rep_extended)
+/* If the machine description for an rtl INSN defines the
+ attr_mode, and that mode is equivalent to a machine_mode, return
+ the corresponding machine_mode. Return MAX_MACHINE_MODE otherwise. */
+DEFHOOK
+(machine_mode_from_attr_mode,
+ "If @var{insn} has an attr_mode that is equivalent to a @code{machine_mode},\
+ return the corresponding @code{machine_mode}, otherwise return\
+ @code{MAX_MACHINE_MODE}.",
+ enum machine_mode, (rtx insn),
+ default_machine_mode_from_attr_mode)
+
/* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
DEFHOOK
(valid_pointer_mode,
Index: ree.c
===================================================================
--- ree.c (revision 192265)
+++ ree.c (working copy)
@@ -756,6 +756,20 @@ combine_reaching_defs (ext_cand *cand, const_rtx s
return false;
}
+/* Given an INSN, obtain the attr_mode specified by the machine
+ description, and map it to the corresponding machine_mode. If the
+ attr_mode isn't specified, return the machine mode for DEST. */
+
+static enum machine_mode
+get_mode (rtx insn, rtx dest)
+{
+ enum machine_mode mode;
+ mode = targetm.machine_mode_from_attr_mode(insn);
+ if (mode == MAX_MACHINE_MODE)
+ mode = GET_MODE (dest);
+ return mode;
+}
+
/* Add an extension pattern that could be eliminated. */
static void
@@ -775,7 +789,7 @@ add_removable_extension (const_rtx expr, rtx insn,
src = SET_SRC (expr);
code = GET_CODE (src);
dest = SET_DEST (expr);
- mode = GET_MODE (dest);
+ mode = get_mode (insn, dest);
if (REG_P (dest)
&& (code == SIGN_EXTEND || code == ZERO_EXTEND)
Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c (revision 192265)
+++ config/i386/i386.c (working copy)
@@ -15074,6 +15074,48 @@ ix86_print_operand_address (FILE *file, rtx addr)
}
}
+/* Implementation of TARGET_MACHINE_MODE_FROM_ATTR_MODE. */
+
+static enum machine_mode
+ix86_machine_mode_from_attr_mode (rtx insn)
+{
+ switch (get_attr_mode (insn))
+ {
+ case MODE_QI:
+ return QImode;
+ case MODE_HI:
+ return HImode;
+ case MODE_SI:
+ return SImode;
+ case MODE_DI:
+ return DImode;
+ case MODE_TI:
+ return TImode;
+ case MODE_OI:
+ return OImode;
+ case MODE_SF:
+ return SFmode;
+ case MODE_DF:
+ return DFmode;
+ case MODE_XF:
+ return XFmode;
+ case MODE_TF:
+ return TFmode;
+ case MODE_V8SF:
+ return V8SFmode;
+ case MODE_V4DF:
+ return V4DFmode;
+ case MODE_V4SF:
+ return V4SFmode;
+ case MODE_V2DF:
+ return V2DFmode;
+ case MODE_V2SF:
+ return V2SFmode;
+ default:
+ return MAX_MACHINE_MODE;
+ }
+}
+
/* Implementation of TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA. */
static bool
@@ -41171,6 +41213,9 @@ ix86_memmodel_check (unsigned HOST_WIDE_INT val)
#undef TARGET_EXPAND_TO_RTL_HOOK
#define TARGET_EXPAND_TO_RTL_HOOK ix86_maybe_switch_abi
+#undef TARGET_MACHINE_MODE_FROM_ATTR_MODE
+#define TARGET_MACHINE_MODE_FROM_ATTR_MODE ix86_machine_mode_from_attr_mode
+
#undef TARGET_LEGITIMATE_ADDRESS_P
#define TARGET_LEGITIMATE_ADDRESS_P ix86_legitimate_address_p
--
This patch is available for review at http://codereview.appspot.com/6631066
