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[RFA] Fix invalid redundant extension elimination for rl78 port

Message ID 5671CB21.70004@redhat.com
State New
Headers show

Commit Message

Jeff Law Dec. 16, 2015, 8:35 p.m. UTC 
On 12/01/2015 12:32 PM, Richard Sandiford wrote:
> Jeff Law <law@redhat.com> writes:
>> @@ -1080,6 +1070,18 @@ add_removable_extension (const_rtx expr, rtx_insn *insn,
>>   	      }
>>   	  }
>>
>> +      /* Fourth, if the extended version occupies more registers than the
>> +	 original and the source of the extension is the same hard register
>> +	 as the destination of the extension, then we can not eliminate
>> +	 the extension without deep analysis, so just punt.
>> +
>> +	 We allow this when the registers are different because the
>> +	 code in combine_reaching_defs will handle that case correctly.  */
>> +      if ((HARD_REGNO_NREGS (REGNO (dest), mode)
>> +	   != HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)))
>> +	  && REGNO (dest) == REGNO (reg))
>> +	return;
>> +
>>         /* Then add the candidate to the list and insert the reaching definitions
>>            into the definition map.  */
>>         ext_cand e = {expr, code, mode, insn};
>
> I might be wrong, but the check looks specific to little-endian.  Would
> it make sense to use reg_overlap_mentioned_p instead of the REGNO check?
Fixed thusly.  Installed on the trunk after the usual testing on 
x86_64-linux-gnu and verifying that rl78-elf doesn't botch pr42833.c.

Jeff
commit 362f406136207b89bddab99f5ff904b0798b7115
Author: law <law@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Wed Dec 16 20:34:31 2015 +0000

    	* ree.c (add_removable_extension): Use reg_overlap_mentioned_p
    	rather than testing hard register #s.
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@231719 138bc75d-0d04-0410-961f-82ee72b054a4
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Patch

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1d2a994..a8475b7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@ 
+2015-12-16  Jeff Law  <law@redhat.com>
+
+	* ree.c (add_removable_extension): Use reg_overlap_mentioned_p
+	rather than testing hard register #s.
+
 2015-12-16  Nathan Sidwell  <nathan@acm.org>
 
 	* config/nvptx/nvptx.h (OUTGOING_STATIC_CHAIN_REGNUM): Remove.
diff --git a/gcc/ree.c b/gcc/ree.c
index 6cfc477..d12e24d 100644
--- a/gcc/ree.c
+++ b/gcc/ree.c
@@ -1085,7 +1085,7 @@  add_removable_extension (const_rtx expr, rtx_insn *insn,
 	 code in combine_reaching_defs will handle that case correctly.  */
       if ((HARD_REGNO_NREGS (REGNO (dest), mode)
 	   != HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)))
-	  && REGNO (dest) == REGNO (reg))
+	  && reg_overlap_mentioned_p (dest, reg))
 	return;
 
       /* Then add the candidate to the list and insert the reaching definitions