[Bug rtl-optimization/42839] [4.5 Regression] gcc.target/mips/octeon-bbit-2.c failing for -mabi=64

[steven at gcc dot gnu dot org]

------- Comment #10 from steven at gcc dot gnu dot org  2010-02-13 11:39 -------
In the test case of comment #2, the history of the funny PHIs is really odd. At
-O2 we end with this in the .optimized dump:

<bb 3>:
  # i_1 = PHI <0(2)>
  # s_11 = PHI <0(2)>

<bb 4>:
  # i_12 = PHI <i_1(3), i_7(4)>
  # s_13 = PHI <s_11(3), s_6(4)>


But the history of the phi of i_12 looks like this:

t.c.120t.reassoc2:  # i_12 = PHI <i_7(3), 0(2)>
t.c.121t.vrp2:  # i_12 = PHI <i_2(3), i_7(7)>
t.c.121t.vrp2:  # i_12 = PHI <0(3), i_7(4)>
t.c.122t.dom2:  # i_12 = PHI <0(3), i_7(4)>
t.c.123t.phicprop2:  # i_12 = PHI <0(2), i_7(3)>
t.c.124t.cddce2:  # i_12 = PHI <i_1(3), i_7(6)>

Somehow we have re-introduced the special PHI "# i_1 = PHI <0(2)>" in the
.cddce2 pass. The reason is that we created a loop pre-header.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42839