1; RUN: llc < %s -march=x86-64 | FileCheck %s 2; CHECK: addl 3 4; The two additions are the same , but have different flags. 5; In theory this code should never be generated by the frontend, but this 6; tries to test that two identical instructions with two different flags 7; actually generate two different nodes. 8; 9; Normally the combiner would see this condition without the flags 10; and optimize the result of the sub into a register clear 11; (the final result would be 0). With the different flags though the combiner 12; needs to keep the add + sub nodes, because the two nodes result as different 13; nodes and so cannot assume that the subtraction of the two nodes 14; generates 0 as result 15define i32 @foo(i32 %a, i32 %b) { 16 %1 = add i32 %a, %b 17 %2 = add nsw i32 %a, %b 18 %3 = sub i32 %1, %2 19 ret i32 %3 20} 21