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[Bug tree-optimization/39999] gcc 4.4.0 compiles in infinite loop
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 2 May 2009 10:19:57 -0000
- Subject: [Bug tree-optimization/39999] gcc 4.4.0 compiles in infinite loop
- References: <bug-39999-11113@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #3 from rguenth at gcc dot gnu dot org 2009-05-02 10:19 -------
Confirmed. I hit
#ifdef ENABLE_CHECKING
/* Theoretically possible, but *highly* unlikely. */
gcc_assert (num_iterations < 500);
#endif
on trunk.
We seem to oscillate
....
ANTIC_IN[12] := { A1_1 (0001), A2_2 (0002), {pointer_plus_expr,A1_1,-4} (0026),
{pointer_plus_expr,A2_2,-4} (0046) }
ANTIC_IN[12] := { A1_1 (0001), A2_2 (0002), {pointer_plus_expr,A2_2,-4} (0025),
{pointer_plus_expr,A2_2,-4} (0046) }
ANTIC_IN[12] := { A1_1 (0001), A2_2 (0002), {pointer_plus_expr,A1_1,-4} (0026),
{pointer_plus_expr,A2_2,-4} (0046) }
ANTIC_IN[12] := { A1_1 (0001), A2_2 (0002), {pointer_plus_expr,A2_2,-4} (0025),
{pointer_plus_expr,A2_2,-4} (0046) }
ANTIC_IN[12] := { A1_1 (0001), A2_2 (0002), {pointer_plus_expr,A1_1,-4} (0026),
{pointer_plus_expr,A2_2,-4} (0046) }
ANTIC_IN[12] := { A1_1 (0001), A2_2 (0002), {pointer_plus_expr,A2_2,-4} (0025),
{pointer_plus_expr,A2_2,-4} (0046) }
Maybe we get confused by the degenerate PHIs
<bb 22>:
<bb 14>:
# A1_17 = PHI <A1_1(22)>
# A2_18 = PHI <A2_2(22)>
C_29 = MMAPMON (p_8(D), A2_18);
D.1783_30 = A2_18 + -4;
free (D.1783_30);
D.1784_31 = A1_17 + -4;
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |dberlin at gcc dot gnu dot
| |org, rguenth at gcc dot gnu
| |dot org
Status|UNCONFIRMED |NEW
Component|middle-end |tree-optimization
Ever Confirmed|0 |1
Keywords| |ice-on-valid-code
Last reconfirmed|0000-00-00 00:00:00 |2009-05-02 10:19:57
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39999