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[Bug rtl-optimization/34826] branch probability is not updated with do-loop optimization
- From: "eres at il dot ibm dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 17 Jan 2008 08:17:45 -0000
- Subject: [Bug rtl-optimization/34826] branch probability is not updated with do-loop optimization
- References: <bug-34826-13229@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #3 from eres at il dot ibm dot com 2008-01-17 08:17 -------
(In reply to comment #2)
> Can you show in an RTL dump why you are sure that the branch probabilities are
> lost?
Sure, I am currently testing a patch we have to fix this problem,
the following '-' lines are from the SMS dump generated with current trunk and
the '+' lines are generated from trunk containing the fix.
@@ -1955,7 +1955,7 @@
(if_then_else (ne:SI (reg:SI 204 [ n ])
(const_int 0 [0x0]))
(label_ref:SI 145)
- (pc))) 356 {*spu.md:3450} (expr_list:REG_BR_PROB (const_int 5000
[0x1388])
+ (pc))) 356 {*spu.md:3450} (expr_list:REG_BR_PROB (const_int 9100
[0x238c])
(nil)))
;; End of basic block 8 -> ( 10 9)
;; lr out 1 [$sp] 127 [$127] 128 [$vfp] 129 [$vap] 176 177 178 179 180
181 183 201 204
@@ -2015,8 +2015,8 @@
;; reg 204 { d110(bb 8 insn 104) }
-;; Succ edge 10 [50.0%] (dfs_back)
-;; Succ edge 9 [50.0%] (fallthru,loop_exit)
+;; Succ edge 10 [91.0%] (dfs_back)
+;; Succ edge 9 [9.0%] (fallthru,loop_exit)
--
eres at il dot ibm dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|branch probability is not |branch probability is not
|reserved with do-loop |updated with do-loop
|optimization |optimization
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34826