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 15 define 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
