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[Bug target/54963] [4.8 Regression] Wrong code generated for libgfortran/generated/eoshift3_8.c on SH


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54963

Kazumoto Kojima <kkojima at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |olegendo at gcc dot gnu.org
          Component|middle-end                  |target
            Summary|Wrong code generated for    |[4.8 Regression] Wrong code
                   |libgfortran/generated/eoshi |generated for
                   |ft3_8.c on SH               |libgfortran/generated/eoshi
                   |                            |ft3_8.c on SH

--- Comment #1 from Kazumoto Kojima <kkojima at gcc dot gnu.org> 2012-10-20 06:33:06 UTC ---
It looks that the problematic code run through a wrong flow
and the above was misleading.  It seems that the change

r184829 | olegendo | 2012-03-03 06:21:13 +0900 (Sat, 03 Mar 2012) | 8 lines

        PR target/49486
        * config/sh/sh.md (negdi2): Add TARGET_SH1 condition.
        (absdi2): New expander.
        (*absdi2, *negabsdi2, negdi_cond): New insns and splits.
        * gcc.target/sh/pr49468-si.c: Skip unsupported test for SH64.
        * gcc.target/sh/pr49468-di.c: New.

causes this.  After reload, there is an insn for abs(sh):

(insn 432 431 1393 39 (set (reg:DI 2 r2)
        (abs:DI (reg:DI 1 r1))) eoshift.c:167 189 {*absdi2}
     (nil))

which is splitted into

(insn 1607 431 1609 39 (set (reg:SI 147 t)
        (ge:SI (reg:SI 2 r2 [+4 ])
            (const_int 0 [0]))) eoshift.c:167 13 {cmpgesi_t}
     (nil))
(insn 1609 1607 1610 39 (set (reg:SI 2 r2)
        (reg:SI 1 r1)) eoshift.c:167 234 {movsi_ie}
     (nil))
(insn 1610 1609 1611 39 (set (reg:SI 3 r3 [+4 ])
        (reg:SI 2 r2 [+4 ])) eoshift.c:167 234 {movsi_ie}
     (nil))
(jump_insn 1611 1610 1626 39 (set (pc)
        (if_then_else (ne (reg:SI 147 t)
                (const_int 0 [0]))
...

The insn 1609 changes r2 before its original value is used.


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