[Bug rtl-optimization/49095] Horrible code generation for trivial decrement with test

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49095

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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  Attachment #24366|0                           |1
        is obsolete|                            |

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-27 11:58:37 UTC ---
Created attachment 24368
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24368
gcc47-pr49095.patch

Improved patch with two new peephole2 patterns, which in addition to the
earlier:
reg0 = mem1; reg0 op= nonmem2; mem1 = reg0; if (reg0 != 0)
optimizes also:
reg0 op= mem1; mem1 = reg0; if (reg0 != 0)
and variant of the first, where all the operations are in QI or HImode, except
for op= which is in SImode.

Again, the patch has been tested just on this testcase so far.