1 ; RUN: opt < %s -simplifycfg -S | FileCheck %s 2 3 ; Test basic folding to a conditional branch. 4 define i32 @foo(i64 %x, i64 %y) nounwind { 5 ; CHECK-LABEL: @foo( 6 entry: 7 %eq = icmp eq i64 %x, %y 8 br i1 %eq, label %b, label %switch 9 switch: 10 %lt = icmp slt i64 %x, %y 11 ; CHECK: br i1 %lt, label %a, label %b 12 %qux = select i1 %lt, i32 0, i32 2 13 switch i32 %qux, label %bees [ 14 i32 0, label %a 15 i32 1, label %b 16 i32 2, label %b 17 ] 18 a: 19 tail call void @bees.a() nounwind 20 ret i32 1 21 ; CHECK: b: 22 ; CHECK-NEXT: %retval = phi i32 [ 0, %switch ], [ 2, %entry ] 23 b: 24 %retval = phi i32 [0, %switch], [0, %switch], [2, %entry] 25 tail call void @bees.b() nounwind 26 ret i32 %retval 27 ; CHECK-NOT: bees: 28 bees: 29 tail call void @llvm.trap() nounwind 30 unreachable 31 } 32 33 ; Test basic folding to an unconditional branch. 34 define i32 @bar(i64 %x, i64 %y) nounwind { 35 ; CHECK-LABEL: @bar( 36 entry: 37 ; CHECK-NEXT: entry: 38 ; CHECK-NEXT: tail call void @bees.a() [[NUW:#[0-9]+]] 39 ; CHECK-NEXT: ret i32 0 40 %lt = icmp slt i64 %x, %y 41 %qux = select i1 %lt, i32 0, i32 2 42 switch i32 %qux, label %bees [ 43 i32 0, label %a 44 i32 1, label %b 45 i32 2, label %a 46 ] 47 a: 48 %retval = phi i32 [0, %entry], [0, %entry], [1, %b] 49 tail call void @bees.a() nounwind 50 ret i32 0 51 b: 52 tail call void @bees.b() nounwind 53 br label %a 54 bees: 55 tail call void @llvm.trap() nounwind 56 unreachable 57 } 58 59 ; Test the edge case where both values from the select are the default case. 60 define void @bazz(i64 %x, i64 %y) nounwind { 61 ; CHECK-LABEL: @bazz( 62 entry: 63 ; CHECK-NEXT: entry: 64 ; CHECK-NEXT: tail call void @bees.b() [[NUW]] 65 ; CHECK-NEXT: ret void 66 %lt = icmp slt i64 %x, %y 67 %qux = select i1 %lt, i32 10, i32 12 68 switch i32 %qux, label %b [ 69 i32 0, label %a 70 i32 1, label %bees 71 i32 2, label %bees 72 ] 73 a: 74 tail call void @bees.a() nounwind 75 ret void 76 b: 77 tail call void @bees.b() nounwind 78 ret void 79 bees: 80 tail call void @llvm.trap() 81 unreachable 82 } 83 84 ; Test the edge case where both values from the select are equal. 85 define void @quux(i64 %x, i64 %y) nounwind { 86 ; CHECK-LABEL: @quux( 87 entry: 88 ; CHECK-NEXT: entry: 89 ; CHECK-NEXT: tail call void @bees.a() [[NUW]] 90 ; CHECK-NEXT: ret void 91 %lt = icmp slt i64 %x, %y 92 %qux = select i1 %lt, i32 0, i32 0 93 switch i32 %qux, label %b [ 94 i32 0, label %a 95 i32 1, label %bees 96 i32 2, label %bees 97 ] 98 a: 99 tail call void @bees.a() nounwind 100 ret void 101 b: 102 tail call void @bees.b() nounwind 103 ret void 104 bees: 105 tail call void @llvm.trap() 106 unreachable 107 } 108 109 ; A final test, for phi node munging. 110 define i32 @xyzzy(i64 %x, i64 %y) { 111 ; CHECK-LABEL: @xyzzy( 112 entry: 113 %eq = icmp eq i64 %x, %y 114 br i1 %eq, label %r, label %cont 115 cont: 116 ; CHECK: %lt = icmp slt i64 %x, %y 117 %lt = icmp slt i64 %x, %y 118 ; CHECK-NEXT: select i1 %lt, i32 -1, i32 1 119 %qux = select i1 %lt, i32 0, i32 2 120 switch i32 %qux, label %bees [ 121 i32 0, label %a 122 i32 1, label %r 123 i32 2, label %r 124 ] 125 r: 126 %val = phi i32 [0, %entry], [1, %cont], [1, %cont] 127 ret i32 %val 128 a: 129 ret i32 -1 130 ; CHECK-NOT: bees: 131 bees: 132 tail call void @llvm.trap() 133 unreachable 134 } 135 136 declare void @llvm.trap() nounwind noreturn 137 declare void @bees.a() nounwind 138 declare void @bees.b() nounwind 139 140 ; CHECK: attributes [[NUW]] = { nounwind } 141 ; CHECK: attributes #1 = { noreturn nounwind } 142
