Summary: If consecutive select instructions are lowered separately in CGP, it will introduce redundant condition check and branches that cannot be removed by later optimization phases. This patch lowers all consecutive select instructions at the same to to avoid inefficent code as demonstrated in https://llvm.org/bugs/show_bug.cgi?id=29095
Reviewers: davidxl
Subscribers: vsk, llvm-commits
Differential Revision: https://reviews.llvm.org/D24147
llvm-svn: 281252
This change improves EmitLoweredSelect() so that multiple contiguous CMOV pseudo
instructions with the same (or exactly opposite) conditions get lowered using a single
new basic-block. This eliminates unnecessary extra basic-blocks (and CFG merge points)
when contiguous CMOVs are being lowered.
Patch by: kevin.b.smith@intel.com
Differential Revision: http://reviews.llvm.org/D11428
llvm-svn: 244202
Dehao Chen