According to Intel Software Optimization Manual on Silvermont in some cases LEA
is better to be replaced with ADD instructions:
"The rule of thumb for ADDs and LEAs is that it is justified to use LEA
with a valid index and/or displacement for non-destructive destination purposes
(especially useful for stack offset cases), or to use a SCALE.
Otherwise, ADD(s) are preferable."
Differential Revision: http://reviews.llvm.org/D3826
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209198 91177308-0d34-0410-b5e6-96231b3b80d8
on ADD16rr opcodes, if src1 != src, since that would cause
convertToThreeAddress to try to create a virtual register. This is not
permitted after register allocation, which is when the X86FixupLEAs pass
runs.
This patch fixes PR16785.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191711 91177308-0d34-0410-b5e6-96231b3b80d8
latency for certain models of the Intel Atom family, by converting
instructions into their equivalent LEA instructions, when it is both
useful and possible to do so.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180573 91177308-0d34-0410-b5e6-96231b3b80d8
