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100 lines
2.2 KiB
LLVM
100 lines
2.2 KiB
LLVM
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; RUN: opt -S -jump-threading < %s | FileCheck %s
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; Check that the heuristic for avoiding accidental introduction of irreducible
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; loops doesn't also prevent us from threading simple constructs where this
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; isn't a problem.
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declare void @opaque_body()
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define void @jump_threading_loopheader() {
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; CHECK-LABEL: @jump_threading_loopheader
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top:
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br label %entry
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entry:
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%ind = phi i32 [0, %top], [%nextind, %latch]
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%nextind = add i32 %ind, 1
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%cmp = icmp ule i32 %ind, 10
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; CHECK: br i1 %cmp, label %latch, label %exit
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br i1 %cmp, label %body, label %latch
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body:
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call void @opaque_body()
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; CHECK: br label %entry
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br label %latch
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latch:
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%cond = phi i2 [1, %entry], [2, %body]
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switch i2 %cond, label %unreach [
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i2 2, label %entry
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i2 1, label %exit
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]
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unreach:
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unreachable
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exit:
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ret void
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}
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; We also need to check the opposite order of the branches, in the switch
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; instruction because jump-threading relies on that to decide which edge to
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; try to thread first.
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define void @jump_threading_loopheader2() {
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; CHECK-LABEL: @jump_threading_loopheader2
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top:
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br label %entry
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entry:
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%ind = phi i32 [0, %top], [%nextind, %latch]
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%nextind = add i32 %ind, 1
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%cmp = icmp ule i32 %ind, 10
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; CHECK: br i1 %cmp, label %exit, label %latch
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br i1 %cmp, label %body, label %latch
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body:
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call void @opaque_body()
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; CHECK: br label %entry
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br label %latch
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latch:
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%cond = phi i2 [1, %entry], [2, %body]
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switch i2 %cond, label %unreach [
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i2 1, label %entry
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i2 2, label %exit
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]
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unreach:
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unreachable
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exit:
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ret void
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}
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; Check if we can handle undef branch condition.
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define void @jump_threading_loopheader3() {
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; CHECK-LABEL: @jump_threading_loopheader3
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top:
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br label %entry
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entry:
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%ind = phi i32 [0, %top], [%nextind, %latch]
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%nextind = add i32 %ind, 1
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%cmp = icmp ule i32 %ind, 10
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; CHECK: br i1 %cmp, label %latch, label %exit
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br i1 %cmp, label %body, label %latch
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body:
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call void @opaque_body()
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; CHECK: br label %entry
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br label %latch
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latch:
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%phi = phi i32 [undef, %entry], [0, %body]
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%cmp1 = icmp eq i32 %phi, 0
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br i1 %cmp1, label %entry, label %exit
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exit:
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ret void
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}
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