[Bug rtl-optimization/20306] New: [4.0/4.1 Regression] FP complex modes moved via GPRs

["dje at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

The patch for PR rtl-opt/15289, changed the behavior of emit_move_insn_1 to 
invoke emit_block_move on memory to memory moves for "optimal behavior", 
instead of invoking a movMM pattern on the inner mode.  emit_block_move 
changes the mode to BLKmode masking the original mode.  This sequence of 
decisions results in GCC choosing GPRs to move a value that explicitly is 
declared floating point in the user code, hurting performance.

-- 
           Summary: [4.0/4.1 Regression] FP complex modes moved via GPRs
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P2
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dje at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org,pthaugen at us dot ibm
                    dot com
 GCC build triplet: powerpc*-*-*
  GCC host triplet: powerpc*-*-*
GCC target triplet: powerpc*-*-*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20306