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; Test the static branch probability heuristics for no-return functions.
; RUN: opt < %s -analyze -branch-prob | FileCheck %s
; RUN: opt < %s -passes='print<branch-prob>' -disable-output 2>&1 | FileCheck %s
declare void @abort() noreturn
define i32 @test1(i32 %a, i32 %b) {
; CHECK: Printing analysis {{.*}} for function 'test1'
entry:
%cond = icmp eq i32 %a, 42
br i1 %cond, label %exit, label %abort
; CHECK: edge entry -> exit probability is 0x7fffffff / 0x80000000 = 100.00% [HOT edge]
; CHECK: edge entry -> abort probability is 0x00000001 / 0x80000000 = 0.00%
abort:
call void @abort() noreturn
unreachable
exit:
ret i32 %b
}
define i32 @test2(i32 %a, i32 %b) {
; CHECK: Printing analysis {{.*}} for function 'test2'
entry:
switch i32 %a, label %exit [i32 1, label %case_a
i32 2, label %case_b
i32 3, label %case_c
i32 4, label %case_d]
; CHECK: edge entry -> exit probability is 0x7ffffffc / 0x80000000 = 100.00% [HOT edge]
; CHECK: edge entry -> case_a probability is 0x00000001 / 0x80000000 = 0.00%
; CHECK: edge entry -> case_b probability is 0x00000001 / 0x80000000 = 0.00%
; CHECK: edge entry -> case_c probability is 0x00000001 / 0x80000000 = 0.00%
; CHECK: edge entry -> case_d probability is 0x00000001 / 0x80000000 = 0.00%
case_a:
br label %case_b
case_b:
br label %case_c
case_c:
br label %case_d
case_d:
call void @abort() noreturn
unreachable
exit:
ret i32 %b
}
define i32 @test3(i32 %a, i32 %b) {
; CHECK: Printing analysis {{.*}} for function 'test3'
; Make sure we unify across multiple conditional branches.
entry:
%cond1 = icmp eq i32 %a, 42
br i1 %cond1, label %exit, label %dom
; CHECK: edge entry -> exit probability is 0x7fffffff / 0x80000000 = 100.00% [HOT edge]
; CHECK: edge entry -> dom probability is 0x00000001 / 0x80000000 = 0.00%
dom:
%cond2 = icmp ult i32 %a, 42
br i1 %cond2, label %idom1, label %idom2
; CHECK: edge dom -> idom1 probability is 0x40000000 / 0x80000000 = 50.00%
; CHECK: edge dom -> idom2 probability is 0x40000000 / 0x80000000 = 50.00%
idom1:
br label %abort
idom2:
br label %abort
abort:
call void @abort() noreturn
unreachable
exit:
ret i32 %b
}
define i32 @test4(i32 %a, i32 %b) {
; CHECK: Printing analysis {{.*}} for function 'test4'
; Make sure we handle loops post-dominated by unreachables.
entry:
%cond1 = icmp eq i32 %a, 42
br i1 %cond1, label %header, label %exit
; CHECK: edge entry -> header probability is 0x00000001 / 0x80000000 = 0.00%
; CHECK: edge entry -> exit probability is 0x7fffffff / 0x80000000 = 100.00% [HOT edge]
header:
br label %body
body:
%cond2 = icmp eq i32 %a, 42
br i1 %cond2, label %header, label %abort
; CHECK: edge body -> header probability is 0x40000000 / 0x80000000 = 50.00%
; CHECK: edge body -> abort probability is 0x40000000 / 0x80000000 = 50.00%
abort:
call void @abort() noreturn
unreachable
exit:
ret i32 %b
}
@_ZTIi = external global i8*
; CHECK-LABEL: throwSmallException
; CHECK-NOT: invoke i32 @smallFunction
define i32 @throwSmallException(i32 %idx, i32 %limit) #0 personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
entry:
%cmp = icmp sge i32 %idx, %limit
br i1 %cmp, label %if.then, label %if.end
; CHECK: edge entry -> if.then probability is 0x00000001 / 0x80000000 = 0.00%
; CHECK: edge entry -> if.end probability is 0x7fffffff / 0x80000000 = 100.00% [HOT edge]
if.then: ; preds = %entry
%exception = call i8* @__cxa_allocate_exception(i64 1) #0
invoke i32 @smallFunction(i32 %idx)
to label %invoke.cont unwind label %lpad
; CHECK: edge if.then -> invoke.cont probability is 0x7ffff800 / 0x80000000 = 100.00% [HOT edge]
; CHECK: edge if.then -> lpad probability is 0x00000800 / 0x80000000 = 0.00%
invoke.cont: ; preds = %if.then
call void @__cxa_throw(i8* %exception, i8* bitcast (i8** @_ZTIi to i8*), i8* null) #1
unreachable
lpad: ; preds = %if.then
%ll = landingpad { i8*, i32 }
cleanup
ret i32 %idx
if.end: ; preds = %entry
ret i32 %idx
}
@a = global i32 4
define i32 @smallFunction(i32 %a) {
entry:
%r = load volatile i32, i32* @a
ret i32 %r
}
attributes #0 = { nounwind }
attributes #1 = { noreturn }
declare i8* @__cxa_allocate_exception(i64)
declare i32 @__gxx_personality_v0(...)
declare void @__cxa_throw(i8*, i8*, i8*)
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