1*9880d681SAndroid Build Coastguard Worker; RUN: opt -S -jump-threading %s | FileCheck %s 2*9880d681SAndroid Build Coastguard Worker; When simplify a branch based on LVI predicates, we should replace the 3*9880d681SAndroid Build Coastguard Worker; comparison itself with a constant (when possible) in case it's otherwise used. 4*9880d681SAndroid Build Coastguard Worker 5*9880d681SAndroid Build Coastguard Workerdefine i32 @test(i32* %p) { 6*9880d681SAndroid Build Coastguard Worker; CHECK-LABEL: @test 7*9880d681SAndroid Build Coastguard Worker; CHECK: icmp eq 8*9880d681SAndroid Build Coastguard Worker; CHECK-NEXT: br i1 %cmp, label %exit2, label %exit1 9*9880d681SAndroid Build Coastguard Worker; CHECK-NOT: icmp ne 10*9880d681SAndroid Build Coastguard Workerentry: 11*9880d681SAndroid Build Coastguard Worker %cmp = icmp eq i32* %p, null 12*9880d681SAndroid Build Coastguard Worker br i1 %cmp, label %is_null, label %not_null 13*9880d681SAndroid Build Coastguard Workeris_null: 14*9880d681SAndroid Build Coastguard Worker %cmp2 = icmp ne i32* %p, null 15*9880d681SAndroid Build Coastguard Worker br i1 %cmp2, label %exit1, label %exit2 16*9880d681SAndroid Build Coastguard Workernot_null: 17*9880d681SAndroid Build Coastguard Worker %cmp3 = icmp ne i32* %p, null 18*9880d681SAndroid Build Coastguard Worker br i1 %cmp3, label %exit1, label %exit2 19*9880d681SAndroid Build Coastguard Workerexit1: 20*9880d681SAndroid Build Coastguard Worker ret i32 0 21*9880d681SAndroid Build Coastguard Workerexit2: 22*9880d681SAndroid Build Coastguard Worker ret i32 1 23*9880d681SAndroid Build Coastguard Worker} 24*9880d681SAndroid Build Coastguard Worker 25*9880d681SAndroid Build Coastguard Workerdeclare void @use(i1) 26*9880d681SAndroid Build Coastguard Worker 27*9880d681SAndroid Build Coastguard Worker; It would not be legal to replace %cmp2 (well, in this case it actually is, 28*9880d681SAndroid Build Coastguard Worker; but that's a CSE problem, not a LVI/jump threading problem) 29*9880d681SAndroid Build Coastguard Workerdefine i32 @test_negative(i32* %p) { 30*9880d681SAndroid Build Coastguard Worker; CHECK-LABEL: @test 31*9880d681SAndroid Build Coastguard Worker; CHECK: icmp ne 32*9880d681SAndroid Build Coastguard Worker; CHECK: icmp eq 33*9880d681SAndroid Build Coastguard Worker; CHECK-NEXT: br i1 %cmp, label %exit2, label %exit1 34*9880d681SAndroid Build Coastguard Worker; CHECK-NOT: icmp ne 35*9880d681SAndroid Build Coastguard Workerentry: 36*9880d681SAndroid Build Coastguard Worker %cmp2 = icmp ne i32* %p, null 37*9880d681SAndroid Build Coastguard Worker call void @use(i1 %cmp2) 38*9880d681SAndroid Build Coastguard Worker %cmp = icmp eq i32* %p, null 39*9880d681SAndroid Build Coastguard Worker br i1 %cmp, label %is_null, label %not_null 40*9880d681SAndroid Build Coastguard Workeris_null: 41*9880d681SAndroid Build Coastguard Worker br i1 %cmp2, label %exit1, label %exit2 42*9880d681SAndroid Build Coastguard Workernot_null: 43*9880d681SAndroid Build Coastguard Worker br i1 %cmp2, label %exit1, label %exit2 44*9880d681SAndroid Build Coastguard Workerexit1: 45*9880d681SAndroid Build Coastguard Worker ret i32 0 46*9880d681SAndroid Build Coastguard Workerexit2: 47*9880d681SAndroid Build Coastguard Worker ret i32 1 48*9880d681SAndroid Build Coastguard Worker} 49*9880d681SAndroid Build Coastguard Worker 50*9880d681SAndroid Build Coastguard Worker; In this case, we can remove cmp2 because it's otherwise unused 51*9880d681SAndroid Build Coastguard Workerdefine i32 @test2(i32* %p) { 52*9880d681SAndroid Build Coastguard Worker; CHECK-LABEL: @test 53*9880d681SAndroid Build Coastguard Worker; CHECK-LABEL: entry: 54*9880d681SAndroid Build Coastguard Worker; CHECK-NEXT: icmp eq 55*9880d681SAndroid Build Coastguard Worker; CHECK-NEXT: br i1 %cmp, label %exit2, label %exit1 56*9880d681SAndroid Build Coastguard Worker; CHECK-NOT: icmp ne 57*9880d681SAndroid Build Coastguard Workerentry: 58*9880d681SAndroid Build Coastguard Worker %cmp2 = icmp ne i32* %p, null 59*9880d681SAndroid Build Coastguard Worker %cmp = icmp eq i32* %p, null 60*9880d681SAndroid Build Coastguard Worker br i1 %cmp, label %is_null, label %not_null 61*9880d681SAndroid Build Coastguard Workeris_null: 62*9880d681SAndroid Build Coastguard Worker br i1 %cmp2, label %exit1, label %exit2 63*9880d681SAndroid Build Coastguard Workernot_null: 64*9880d681SAndroid Build Coastguard Worker br i1 %cmp2, label %exit1, label %exit2 65*9880d681SAndroid Build Coastguard Workerexit1: 66*9880d681SAndroid Build Coastguard Worker ret i32 0 67*9880d681SAndroid Build Coastguard Workerexit2: 68*9880d681SAndroid Build Coastguard Worker ret i32 1 69*9880d681SAndroid Build Coastguard Worker} 70