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[Bug rtl-optimization/32084] gfortran 4.3 13%-18% slower for induct.f90 than gcc 4.0-based competitor
- From: "ubizjak at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 28 Jun 2007 09:20:19 -0000
- Subject: [Bug rtl-optimization/32084] gfortran 4.3 13%-18% slower for induct.f90 than gcc 4.0-based competitor
- References: <bug-32084-13404@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #10 from ubizjak at gmail dot com 2007-06-28 09:20 -------
Well, well - what can be found in _.146r.loop_unroll:
Loop 10 is simple:
simple exit 40 -> 42
number of iterations: (const_int 8 [0x8])
upper bound: 8
;; Unable to prove that the loop rolls exactly once
;; Considering peeling completely
;; Not peeling loop completely, rolls too much (8 iterations > 8 [maximum
peelings])
Really funny... Since when is "8 more than 8"? ;(
However, gcc has no problems when unrolling without --ftree-vectorize:
Loop 8 is simple:
simple exit 28 -> 30
number of iterations: (const_int 8 [0x8])
upper bound: 8
;; Unable to prove that the loop rolls exactly once
;; Considering peeling completely
;; Decided to peel loop completely
Investigating...
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32084