[Bug bootstrap/44970] [4.6 regression] Revision 162270 failed to bootstrap

["bernds at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #27 from bernds at gcc dot gnu dot org  2010-07-18 21:00 -------
(In reply to comment #26)
> Subject: Re:  [4.6 regression] Revision 162270 failed to bootstrap
> 
> Doing a non bootstrap build, I see the following new fail:
> FAIL: gcc.c-torture/execute/950605-1.c execution,  -O1

David, this seems to be caused by a different revision.  The postreload pass
we're discussing here makes no changes to RTL on that testcase.  Please ensure
you find the right revision that introduces a problem.

In this case, it probably was another of my changes that caused this failure,
although I can't tell what's wrong.  The extend insn disappears during fwprop1:

-(insn 3 5 4 2 950605-1.c:3 (set (reg/v:DI 68 [ c+-7 ])
-        (zero_extend:DI (reg:SI 26 %r26 [ c+-3 ]))) 133 {*pa.md:4633} (nil))
+(note 5 0 4 2 [bb 2] NOTE_INSN_BASIC_BLOCK)

-(note 4 3 7 2 NOTE_INSN_FUNCTION_BEG)
+(note 4 5 7 2 NOTE_INSN_FUNCTION_BEG)

 (insn 7 4 8 2 950605-1.c:4 (set (reg:SI 69)
         (const_int 255 [0xff])) 71 {*pa.md:2130} (nil))

 (jump_insn 8 7 9 2 950605-1.c:4 (set (pc)
-        (if_then_else (eq (subreg/s/u:SI (reg/v:DI 68 [ c+-7 ]) 4)
+        (if_then_else (eq (reg:SI 26 %r26 [ c+-3 ])
                 (reg:SI 69))
             (label_ref:DI 23)
-            (pc))) 46 {*pa.md:1330} (expr_list:REG_BR_PROB (const_int 9996
[0x270c])
-        (nil))
+            (pc))) 46 {*pa.md:1330} (expr_list:REG_DEAD (reg:SI 69)
+        (expr_list:REG_DEAD (reg/v:DI 68 [ c+-7 ])
+            (expr_list:REG_BR_PROB (const_int 9996 [0x270c])
+                (nil))))

I can't find anything wrong with this, as it's a SImode comparison.  Is the
backend emitting the correct compare instruction?


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44970