diff --git a/lib/Target/README.txt b/lib/Target/README.txt index 9831efbdf64..93e8c54979d 100644 --- a/lib/Target/README.txt +++ b/lib/Target/README.txt @@ -971,3 +971,17 @@ int main() { //===---------------------------------------------------------------------===// +Instcombine will merge comparisons like (x >= 10) && (x < 20) by producing (x - +10) u< 10, but only when the comparisons have matching sign. + +This could be converted with a similiar technique. (PR1941) + +define i1 @test(i8 %x) { + %A = icmp uge i8 %x, 5 + %B = icmp slt i8 %x, 20 + %C = and i1 %A, %B + ret i1 %C +} + +//===---------------------------------------------------------------------===// +