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
