105 lines
2.4 KiB
LLVM
105 lines
2.4 KiB
LLVM
; RUN: opt -S -jump-threading %s | FileCheck %s
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; Value of predicate known on all inputs (trivial case)
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; Note: InstCombine/EarlyCSE would also get this case
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define void @test(i8* %p, i8** %addr) {
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; CHECK-LABEL: @test
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entry:
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%cmp0 = icmp eq i8* %p, null
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br i1 %cmp0, label %exit, label %loop
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loop:
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; CHECK-LABEL: loop:
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; CHECK-NEXT: phi
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; CHECK-NEXT: br label %loop
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%p1 = phi i8* [%p, %entry], [%p1, %loop]
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%cmp1 = icmp eq i8* %p1, null
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br i1 %cmp1, label %exit, label %loop
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exit:
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ret void
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}
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; Value of predicate known on all inputs (non-trivial)
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define void @test2(i8* %p) {
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; CHECK-LABEL: @test2
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entry:
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%cmp0 = icmp eq i8* %p, null
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br i1 %cmp0, label %exit, label %loop
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loop:
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%p1 = phi i8* [%p, %entry], [%p2, %backedge]
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%cmp1 = icmp eq i8* %p1, null
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br i1 %cmp1, label %exit, label %backedge
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backedge:
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; CHECK-LABEL: backedge:
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; CHECK-NEXT: phi
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; CHECK-NEXT: bitcast
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; CHECK-NEXT: load
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; CHECK-NEXT: cmp
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; CHECK-NEXT: br
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; CHECK-DAG: label %backedge
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%addr = bitcast i8* %p1 to i8**
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%p2 = load i8*, i8** %addr
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%cmp2 = icmp eq i8* %p2, null
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br i1 %cmp2, label %exit, label %loop
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exit:
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ret void
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}
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; If the inputs don't branch the same way, we can't rewrite
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; Well, we could unroll this loop exactly twice, but that's
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; a different transform.
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define void @test_mixed(i8* %p) {
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; CHECK-LABEL: @test_mixed
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entry:
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%cmp0 = icmp eq i8* %p, null
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br i1 %cmp0, label %exit, label %loop
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loop:
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; CHECK-LABEL: loop:
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; CHECK-NEXT: phi
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; CHECK-NEXT: %cmp1 = icmp
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; CHECK-NEXT: br i1 %cmp1
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%p1 = phi i8* [%p, %entry], [%p1, %loop]
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%cmp1 = icmp ne i8* %p1, null
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br i1 %cmp1, label %exit, label %loop
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exit:
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ret void
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}
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; The eq predicate is always true if we go through the path from
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; L1 to L3, no matter the phi result %t5 is on the lhs or rhs of
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; the predicate.
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declare void @goo()
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declare void @hoo()
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define void @test3(i32 %m, i32** %t1) {
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L1:
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%t0 = add i32 %m, 7
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%t2 = load i32*, i32** %t1, align 8
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; CHECK-LABEL: @test3
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; CHECK: %t3 = icmp eq i32* %t2, null
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; CHECK: br i1 %t3, label %[[LABEL2:.*]], label %[[LABEL1:.*]]
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%t3 = icmp eq i32* %t2, null
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br i1 %t3, label %L3, label %L2
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; CHECK: [[LABEL1]]:
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; CHECK-NEXT: %t4 = load i32, i32* %t2, align 4
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L2:
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%t4 = load i32, i32* %t2, align 4
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br label %L3
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L3:
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%t5 = phi i32 [ %t0, %L1 ], [ %t4, %L2 ]
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%t6 = icmp eq i32 %t0, %t5
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br i1 %t6, label %L4, label %L5
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; CHECK: [[LABEL2]]:
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; CHECK-NEXT: call void @goo()
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L4:
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call void @goo()
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ret void
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L5:
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call void @hoo()
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ret void
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}
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