SI_IF and SI_ELSE are terminators which also produce a value. For
these instructions ISel always inserts a COPY to move their value
to another basic block. This COPY ends up between SI_(IF|ELSE)
and the S_BRANCH* instruction at the end of the block.
This breaks MachineBasicBlock::getFirstTerminator() and also the
machine verifier which assumes that terminators are grouped together at
the end of blocks.
To solve this we coalesce the copy away right after ISel to make sure
there are no instructions in between terminators at the end of blocks.
llvm-svn: 207591
This is a squash of several optimization commits:
- calculate DIV_Lo and DIV_Hi separately
- use BFE_U32 if we are operating on 32bit values
- use precomputed constants instead of shifting in UDVIREM
- skip the first 32 iterations of udivrem
v2: Check whether BFE is supported before using it
Patch by: Jan Vesely
Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
llvm-svn: 207589
