llvm-project/llvm/lib/Target/ARM/README.txt

//===---------------------------------------------------------------------===//
// Random ideas for the ARM backend.
//===---------------------------------------------------------------------===//

Consider implementing a select with two conditional moves:

cmp x, y
moveq dst, a
movne dst, b

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%tmp1 = shl int %b, ubyte %c
%tmp4 = add int %a, %tmp1

compiles to

add r0, r0, r1, lsl r2

but

%tmp1 = shl int %b, ubyte %c
%tmp4 = add int %tmp1, %a

compiles to
mov r1, r1, lsl r2
add r0, r1, r0

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add an offset to FLDS/FLDD addressing mode

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