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re PR rtl-optimization/54900 (write introduction incorrect wrt the C11 memory model (2))

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PR rtl-optimization/54900
	* ifcvt.c (noce_can_store_speculate_p): Call
	memory_must_be_modified_in_insn_p.
	* alias.c (memory_must_be_modified_in_insn_p): New.
	(set_dest_equal_p): New.
	* rtl.h (memory_must_be_modified_in_p): Protoize.

From-SVN: r192548
This commit is contained in:
Aldy Hernandez 2012-10-17 20:59:40 +00:00 • committed by Aldy Hernandez
parent 4d9675496a
commit a7b159a4dc
4 changed files with 44 additions and 1 deletions
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9
gcc/ChangeLog
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@ -1,3 +1,12 @@
2012-10-17 Aldy Hernandez <aldyh@redhat.com>
PR rtl-optimization/54900
* ifcvt.c (noce_can_store_speculate_p): Call
memory_must_be_modified_in_insn_p.
* alias.c (memory_must_be_modified_in_insn_p): New.
(set_dest_equal_p): New.
* rtl.h (memory_must_be_modified_in_p): Protoize.
2012-10-17 Michael Meissner <meissner@linux.vnet.ibm.com>
* config/rs6000/rs6000.opt (rs6000_isa_flags): New flag word to

33
gcc/alias.c
View file

@ -2762,6 +2762,39 @@ memory_modified_in_insn_p (const_rtx mem, const_rtx insn)
return memory_modified;
}
/* Return TRUE if the destination of a set is rtx identical to
ITEM. */
static inline bool
set_dest_equal_p (const_rtx set, const_rtx item)
{
rtx dest = SET_DEST (set);
return rtx_equal_p (dest, item);
}
/* Like memory_modified_in_insn_p, but return TRUE if INSN will
*DEFINITELY* modify the memory contents of MEM. */
bool
memory_must_be_modified_in_insn_p (const_rtx mem, const_rtx insn)
{
if (!INSN_P (insn))
return false;
insn = PATTERN (insn);
if (GET_CODE (insn) == SET)
return set_dest_equal_p (insn, mem);
else if (GET_CODE (insn) == PARALLEL)
{
int i;
for (i = 0; i < XVECLEN (insn, 0); i++)
{
rtx sub = XVECEXP (insn, 0, i);
if (GET_CODE (sub) == SET
&& set_dest_equal_p (sub, mem))
return true;
}
}
return false;
}
/* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE
array. */

2
gcc/ifcvt.c
View file

@ -2415,7 +2415,7 @@ noce_can_store_speculate_p (basic_block top_bb, const_rtx mem)
|| (CALL_P (insn) && (!RTL_CONST_CALL_P (insn)))))
return false;
if (memory_modified_in_insn_p (mem, insn))
if (memory_must_be_modified_in_insn_p (mem, insn))
return true;
if (modified_in_p (XEXP (mem, 0), insn))
return false;

1
gcc/rtl.h
View file

@ -2616,6 +2616,7 @@ extern void init_alias_analysis (void);
extern void end_alias_analysis (void);
extern void vt_equate_reg_base_value (const_rtx, const_rtx);
extern bool memory_modified_in_insn_p (const_rtx, const_rtx);
extern bool memory_must_be_modified_in_insn_p (const_rtx, const_rtx);
extern bool may_be_sp_based_p (rtx);
extern rtx gen_hard_reg_clobber (enum machine_mode, unsigned int);
extern rtx get_reg_known_value (unsigned int);