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; RUN: opt -S -jump-threading %s | FileCheck %s
; Value of predicate known on all inputs (trivial case)
; Note: InstCombine/EarlyCSE would also get this case
define void @test(i8* %p, i8** %addr) {
; CHECK-LABEL: @test
entry:
%cmp0 = icmp eq i8* %p, null
br i1 %cmp0, label %exit, label %loop
loop:
; CHECK-LABEL: loop:
; CHECK-NEXT: phi
; CHECK-NEXT: br label %loop
%p1 = phi i8* [%p, %entry], [%p1, %loop]
%cmp1 = icmp eq i8* %p1, null
br i1 %cmp1, label %exit, label %loop
exit:
ret void
}
; Value of predicate known on all inputs (non-trivial)
define void @test2(i8* %p) {
; CHECK-LABEL: @test2
entry:
%cmp0 = icmp eq i8* %p, null
br i1 %cmp0, label %exit, label %loop
loop:
%p1 = phi i8* [%p, %entry], [%p2, %backedge]
%cmp1 = icmp eq i8* %p1, null
br i1 %cmp1, label %exit, label %backedge
backedge:
; CHECK-LABEL: backedge:
; CHECK-NEXT: phi
; CHECK-NEXT: bitcast
; CHECK-NEXT: load
; CHECK-NEXT: cmp
; CHECK-NEXT: br
; CHECK-DAG: label %backedge
%addr = bitcast i8* %p1 to i8**
%p2 = load i8*, i8** %addr
%cmp2 = icmp eq i8* %p2, null
br i1 %cmp2, label %exit, label %loop
exit:
ret void
}
; If the inputs don't branch the same way, we can't rewrite
; Well, we could unroll this loop exactly twice, but that's
; a different transform.
define void @test_mixed(i8* %p) {
; CHECK-LABEL: @test_mixed
entry:
%cmp0 = icmp eq i8* %p, null
br i1 %cmp0, label %exit, label %loop
loop:
; CHECK-LABEL: loop:
; CHECK-NEXT: phi
; CHECK-NEXT: %cmp1 = icmp
; CHECK-NEXT: br i1 %cmp1
%p1 = phi i8* [%p, %entry], [%p1, %loop]
%cmp1 = icmp ne i8* %p1, null
br i1 %cmp1, label %exit, label %loop
exit:
ret void
}
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