1 ; Test the static branch probability heuristics for no-return functions. 2 ; RUN: opt < %s -analyze -branch-prob | FileCheck %s 3 ; RUN: opt < %s -passes='print<branch-prob>' -disable-output 2>&1 | FileCheck %s 4 5 declare void @abort() noreturn 6 7 define i32 @test1(i32 %a, i32 %b) { 8 ; CHECK: Printing analysis {{.*}} for function 'test1' 9 entry: 10 %cond = icmp eq i32 %a, 42 11 br i1 %cond, label %exit, label %abort 12 ; CHECK: edge entry -> exit probability is 0x7ffff800 / 0x80000000 = 100.00% [HOT edge] 13 ; CHECK: edge entry -> abort probability is 0x00000800 / 0x80000000 = 0.00% 14 15 abort: 16 call void @abort() noreturn 17 unreachable 18 19 exit: 20 ret i32 %b 21 } 22 23 define i32 @test2(i32 %a, i32 %b) { 24 ; CHECK: Printing analysis {{.*}} for function 'test2' 25 entry: 26 switch i32 %a, label %exit [i32 1, label %case_a 27 i32 2, label %case_b 28 i32 3, label %case_c 29 i32 4, label %case_d] 30 ; CHECK: edge entry -> exit probability is 0x7ffff800 / 0x80000000 = 100.00% [HOT edge] 31 ; CHECK: edge entry -> case_a probability is 0x00000200 / 0x80000000 = 0.00% 32 ; CHECK: edge entry -> case_b probability is 0x00000200 / 0x80000000 = 0.00% 33 ; CHECK: edge entry -> case_c probability is 0x00000200 / 0x80000000 = 0.00% 34 ; CHECK: edge entry -> case_d probability is 0x00000200 / 0x80000000 = 0.00% 35 36 case_a: 37 br label %case_b 38 39 case_b: 40 br label %case_c 41 42 case_c: 43 br label %case_d 44 45 case_d: 46 call void @abort() noreturn 47 unreachable 48 49 exit: 50 ret i32 %b 51 } 52 53 define i32 @test3(i32 %a, i32 %b) { 54 ; CHECK: Printing analysis {{.*}} for function 'test3' 55 ; Make sure we unify across multiple conditional branches. 56 entry: 57 %cond1 = icmp eq i32 %a, 42 58 br i1 %cond1, label %exit, label %dom 59 ; CHECK: edge entry -> exit probability is 0x7ffff800 / 0x80000000 = 100.00% [HOT edge] 60 ; CHECK: edge entry -> dom probability is 0x00000800 / 0x80000000 = 0.00% 61 62 dom: 63 %cond2 = icmp ult i32 %a, 42 64 br i1 %cond2, label %idom1, label %idom2 65 ; CHECK: edge dom -> idom1 probability is 0x40000000 / 0x80000000 = 50.00% 66 ; CHECK: edge dom -> idom2 probability is 0x40000000 / 0x80000000 = 50.00% 67 68 idom1: 69 br label %abort 70 71 idom2: 72 br label %abort 73 74 abort: 75 call void @abort() noreturn 76 unreachable 77 78 exit: 79 ret i32 %b 80 } 81 82 @_ZTIi = external global i8* 83 84 ; CHECK-LABEL: throwSmallException 85 ; CHECK-NOT: invoke i32 @smallFunction 86 define i32 @throwSmallException(i32 %idx, i32 %limit) #0 personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) { 87 entry: 88 %cmp = icmp sge i32 %idx, %limit 89 br i1 %cmp, label %if.then, label %if.end 90 ; CHECK: edge entry -> if.then probability is 0x00000800 / 0x80000000 = 0.00% 91 ; CHECK: edge entry -> if.end probability is 0x7ffff800 / 0x80000000 = 100.00% [HOT edge] 92 93 if.then: ; preds = %entry 94 %exception = call i8* @__cxa_allocate_exception(i64 1) #0 95 invoke i32 @smallFunction(i32 %idx) 96 to label %invoke.cont unwind label %lpad 97 ; CHECK: edge if.then -> invoke.cont probability is 0x7ffff800 / 0x80000000 = 100.00% [HOT edge] 98 ; CHECK: edge if.then -> lpad probability is 0x00000800 / 0x80000000 = 0.00% 99 100 invoke.cont: ; preds = %if.then 101 call void @__cxa_throw(i8* %exception, i8* bitcast (i8** @_ZTIi to i8*), i8* null) #1 102 unreachable 103 104 lpad: ; preds = %if.then 105 %ll = landingpad { i8*, i32 } 106 cleanup 107 ret i32 %idx 108 109 if.end: ; preds = %entry 110 ret i32 %idx 111 } 112 113 @a = global i32 4 114 define i32 @smallFunction(i32 %a) { 115 entry: 116 %r = load volatile i32, i32* @a 117 ret i32 %r 118 } 119 120 attributes #0 = { nounwind } 121 attributes #1 = { noreturn } 122 123 declare i8* @__cxa_allocate_exception(i64) 124 declare i32 @__gxx_personality_v0(...) 125 declare void @__cxa_throw(i8*, i8*, i8*) 126
