1 ; RUN: opt < %s -sccp -S | FileCheck %s 2 3 ; This is a basic sanity check for constant propagation. The add instruction 4 ; should be eliminated. 5 6 define i32 @test1(i1 %B) { 7 br i1 %B, label %BB1, label %BB2 8 BB1: ; preds = %0 9 %Val = add i32 0, 0 ; <i32> [#uses=1] 10 br label %BB3 11 BB2: ; preds = %0 12 br label %BB3 13 BB3: ; preds = %BB2, %BB1 14 %Ret = phi i32 [ %Val, %BB1 ], [ 1, %BB2 ] ; <i32> [#uses=1] 15 ret i32 %Ret 16 17 ; CHECK-LABEL: @test1( 18 ; CHECK: %Ret = phi i32 [ 0, %BB1 ], [ 1, %BB2 ] 19 } 20 21 ; This is the test case taken from appel's book that illustrates a hard case 22 ; that SCCP gets right. 23 ; 24 define i32 @test2(i32 %i0, i32 %j0) { 25 ; CHECK-LABEL: @test2( 26 BB1: 27 br label %BB2 28 BB2: 29 %j2 = phi i32 [ %j4, %BB7 ], [ 1, %BB1 ] 30 %k2 = phi i32 [ %k4, %BB7 ], [ 0, %BB1 ] 31 %kcond = icmp slt i32 %k2, 100 32 br i1 %kcond, label %BB3, label %BB4 33 BB3: 34 %jcond = icmp slt i32 %j2, 20 35 br i1 %jcond, label %BB5, label %BB6 36 ; CHECK: BB3: 37 ; CHECK-NEXT: br i1 true, label %BB5, label %BB6 38 BB4: 39 ret i32 %j2 40 ; CHECK: BB4: 41 ; CHECK-NEXT: ret i32 1 42 BB5: 43 %k3 = add i32 %k2, 1 44 br label %BB7 45 BB6: 46 %k5 = add i32 %k2, 1 47 br label %BB7 48 ; CHECK: BB6: 49 ; CHECK-NEXT: br label %BB7 50 BB7: 51 %j4 = phi i32 [ 1, %BB5 ], [ %k2, %BB6 ] 52 %k4 = phi i32 [ %k3, %BB5 ], [ %k5, %BB6 ] 53 br label %BB2 54 ; CHECK: BB7: 55 ; CHECK-NEXT: %k4 = phi i32 [ %k3, %BB5 ], [ undef, %BB6 ] 56 ; CHECK-NEXT: br label %BB2 57 } 58 59
