[Bug middle-end/36177] [4.4 Regression] g++.dg/opt/pr23714.C ICEs with 135041 -> 135057
zadeck at naturalbridge dot com
gcc-bugzilla@gcc.gnu.org
Fri May 9 12:26:00 GMT 2008
------- Comment #11 from zadeck at naturalbridge dot com 2008-05-09 12:25 -------
Subject: Re: [4.4 Regression] g++.dg/opt/pr23714.C
ICEs with 135041 -> 135057
zadeck at naturalbridge dot com wrote:
> ------- Comment #10 from zadeck at naturalbridge dot com 2008-05-09 11:58 -------
> Subject: Re: [4.4 Regression] g++.dg/opt/pr23714.C
> ICEs with 135041 -> 135057
>
> bonzini at gnu dot org wrote:
>
>> ------- Comment #9 from bonzini at gnu dot org 2008-05-09 11:32 -------
>> You know I'm still not sure if I can review patches outside df* (i.e. files
>> that do what flow.c did, but are not dataflow related), but if you think I
>> can... then patch is ok. :-)
>>
>>
>>
>>
> I had talked to david last time you raised this issue and he indicated
> that he thought it was fine.
> If someone objects, the patch can be reversed.
>
> Thanks
>
> Kenny
>
>
>
commit as 135113.
2008-05-08 Kenneth Zadeck <zadeck@naturalbridge.com>
PR middle-end/36117
* dce.c (deletable_insn_p): Do not delete calls if
df_in_progress.
(delete_unmarked_insns): When deleting a call, call
delete_unreachable_blocks.
* rtl.texi (RTL_CONST_CALL_P, RTL_PURE_CALL_P,
RTL_CONST_OR_PURE_CALL_P, RTL_LOOPING_CONST_OR_PURE_CALL_P): Fixed
doc.
Index: doc/rtl.texi
===================================================================
--- doc/rtl.texi (revision 135089)
+++ doc/rtl.texi (working copy)
@@ -559,13 +559,36 @@ In either case GCC assumes these address
perhaps with the help of base registers.
Stored in the @code{unchanging} field and printed as @samp{/u}.
-@findex CONST_OR_PURE_CALL_P
+@findex RTL_CONST_CALL_P
@cindex @code{call_insn} and @samp{/u}
@cindex @code{unchanging}, in @code{call_insn}
-@item CONST_OR_PURE_CALL_P (@var{x})
-In a @code{call_insn}, @code{note}, or an @code{expr_list} for notes,
-indicates that the insn represents a call to a const or pure function.
-Stored in the @code{unchanging} field and printed as @samp{/u}.
+@item RTLCONST_OR_PURE_CALL_P (@var{x})
+In a @code{call_insn} indicates that the insn represents a call to a
+const function. Stored in the @code{unchanging} field and printed as
+@samp{/u}.
+
+@findex RTL_PURE_CALL_P
+@cindex @code{call_insn} and @samp{/i}
+@cindex @code{return_val}, in @code{call_insn}
+@item RTLCONST_OR_PURE_CALL_P (@var{x})
+In a @code{call_insn} indicates that the insn represents a call to a
+pure function. Stored in the @code{return_val} field and printed as
+@samp{/i}.
+
+@findex RTL_CONST_OR_PURE_CALL_P
+@cindex @code{call_insn} and @samp{/u} or @samp{/i}
+@item RTL_CONST_OR_PURE_CALL_P (@var{x})
+In a @code{call_insn}, true if @code{RTL_CONST_CALL_P} or
+@code{RTL_PURE_CALL_P} is true.
+
+@findex RTL_LOOPING_CONST_OR_PURE_CALL_P
+@cindex @code{call_insn} and @samp{/c}
+@cindex @code{call}, in @code{call_insn}
+@item RTL_LOOPING_CONST_OR_PURE_CALL_P (@var{x})
+In a @code{call_insn} indicates that the insn represents a possibly
+infinite looping call to a const or pure function. Stored in the
+@code{call} field and printed as @samp{/c}. Only true if one of
+@code{RTL_CONST_CALL_P} or @code{RTL_PURE_CALL_P} is true.
@findex INSN_ANNULLED_BRANCH_P
@cindex @code{jump_insn} and @samp{/u}
@@ -869,6 +892,9 @@ These are the fields to which the above
@item call
In a @code{mem}, 1 means that the memory reference will not trap.
+In a @code{call}, 1 means that this pure or const call may possibly
+infinite loop.
+
In an RTL dump, this flag is represented as @samp{/c}.
@findex frame_related
@@ -938,6 +964,8 @@ known not to be a member of a structure,
In @code{symbol_ref} expressions, 1 means the referenced symbol is weak.
+In @code{call} expressions, 1 means the call is pure.
+
In an RTL dump, this flag is represented as @samp{/i}.
@findex jump
@@ -967,8 +995,8 @@ instruction, 1 means an annulling branch
In a @code{symbol_ref} expression, 1 means that this symbol addresses
something in the per-function constant pool.
-In a @code{call_insn}, @code{note}, or an @code{expr_list} of notes,
-1 means that this instruction is a call to a const or pure function.
+In a @code{call_insn} 1 means that this instruction is a call to a const
+function.
In an RTL dump, this flag is represented as @samp{/u}.
Index: dce.c
===================================================================
--- dce.c (revision 135089)
+++ dce.c (working copy)
@@ -99,11 +99,16 @@ deletable_insn_p (rtx insn, bool fast)
rtx body, x;
int i;
- /* We can delete dead const or pure calls as long as they do not
- infinite loop and are not sibling calls. The problem with
- sibling calls is that it is hard to see the result. */
- if (CALL_P (insn)
+ if (CALL_P (insn)
+ /* We cannot delete calls inside of the recursive dce because
+ this may cause basic blocks to be deleted and this messes up
+ the rest of the stack of optimization passes. */
+ && (!df_in_progress)
+ /* We cannot delete pure or const sibling calls because it is
+ hard to see the result. */
&& (!SIBLING_CALL_P (insn))
+ /* We can delete dead const or pure calls as long as they do not
+ infinite loop. */
&& (RTL_CONST_OR_PURE_CALL_P (insn)
&& !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)))
return true;
@@ -305,6 +310,7 @@ delete_unmarked_insns (void)
{
basic_block bb;
rtx insn, next;
+ bool must_clean = false;
FOR_EACH_BB (bb)
FOR_BB_INSNS_SAFE (bb, insn, next)
@@ -382,9 +388,19 @@ delete_unmarked_insns (void)
remove_note (XEXP (note, 0), libcall_note);
}
+ /* If a pure or const call is deleted, this may make the cfg
+ have unreachable blocks. We rememeber this and call
+ delete_unreachable_blocks at the end. */
+ if (CALL_P (insn))
+ must_clean = true;
+
/* Now delete the insn. */
delete_insn_and_edges (insn);
}
+
+ /* Deleted a pure or const call. */
+ if (must_clean)
+ delete_unreachable_blocks ();
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36177
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