Extended Description

See, for example:

$ opt -div-rem-pairs Transforms/DivRemPairs/X86/div-rem-pairs.ll

define void @​decompose_illegal_srem_same_block(i32 %a, i32 %b) {
%rem = srem i32 %a, %b
%div = sdiv i32 %a, %b
call void @​foo(i32 %rem, i32 %div)
ret void
}
=>
define void @​decompose_illegal_srem_same_block(i32 %a, i32 %b) {
%div = sdiv i32 %a, %b
%1 = mul i32 %div, %b
%2 = sub i32 %a, %1
call void @​foo(i32 %2, i32 %div)
ret void
}
Transformation doesn't verify!
ERROR: Source is more defined than target

Example:
i32 %a = undef
i32 %b = #x00000001 (1)

Source:
i32 %rem = #x00000000 (0)
i32 %div = undef

Target:
i32 %div = #x7fffffff (2147483647)
i32 %1 = undef
i32 %2 = undef