[Bug middle-end/54154] cprop_hardreg generates redundant instructions

[Paulo.Matos at csr dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54154

--- Comment #2 from Paulo J. Matos <Paulo.Matos at csr dot com> 2012-08-01 14:37:53 UTC ---
Created attachment 27924
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27924
Add debug info when redundant insn is going to be generated

Looking at the gcc log header after running cprop_hardreg shows:

rescanning insn with uid = 14.
deleting insn with uid = 14.
insn 14: replaced reg 0 with 1
insn 48: replaced reg 0 with 1
rescanning insn with uid = 48.
deleting insn with uid = 48.
rescanning insn with uid = 5.
deleting insn with uid = 5.
oops, substitution makes dest same as src
insn 5: replaced reg 0 with 1