2010-12-15 09:51:20 +00:00
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; RUN: opt -S -jump-threading < %s | FileCheck %s
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declare void @foo()
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declare void @bar()
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declare void @baz()
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declare void @quux()
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; Jump threading of branch with select as condition.
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; Mostly theoretical since instruction combining simplifies all selects of
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; booleans where at least one operand is true/false/undef.
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2013-07-14 01:42:54 +00:00
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; CHECK-LABEL: @test_br(
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2010-12-15 09:51:20 +00:00
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 %cond, label %L1,
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define void @test_br(i1 %cond, i1 %value) nounwind {
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entry:
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br i1 %cond, label %L0, label %L3
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L0:
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%expr = select i1 %cond, i1 true, i1 %value
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br i1 %expr, label %L1, label %L2
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L1:
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call void @foo()
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ret void
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L2:
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call void @bar()
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ret void
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L3:
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call void @baz()
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br label %L0
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}
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; Jump threading of switch with select as condition.
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2013-07-14 01:42:54 +00:00
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; CHECK-LABEL: @test_switch(
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2010-12-15 09:51:20 +00:00
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 %cond, label %L1,
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define void @test_switch(i1 %cond, i8 %value) nounwind {
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entry:
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br i1 %cond, label %L0, label %L4
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L0:
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%expr = select i1 %cond, i8 1, i8 %value
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switch i8 %expr, label %L3 [i8 1, label %L1 i8 2, label %L2]
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L1:
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call void @foo()
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ret void
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L2:
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call void @bar()
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ret void
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L3:
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call void @baz()
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ret void
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L4:
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call void @quux()
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br label %L0
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}
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; Make sure the blocks in the indirectbr test aren't trivially removable as
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; successors by taking their addresses.
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@anchor = constant [3 x i8*] [
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i8* blockaddress(@test_indirectbr, %L1),
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i8* blockaddress(@test_indirectbr, %L2),
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i8* blockaddress(@test_indirectbr, %L3)
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]
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; Jump threading of indirectbr with select as address.
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2013-07-14 01:42:54 +00:00
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; CHECK-LABEL: @test_indirectbr(
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2010-12-15 09:51:20 +00:00
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 %cond, label %L1, label %L3
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define void @test_indirectbr(i1 %cond, i8* %address) nounwind {
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entry:
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br i1 %cond, label %L0, label %L3
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L0:
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%indirect.goto.dest = select i1 %cond, i8* blockaddress(@test_indirectbr, %L1), i8* %address
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indirectbr i8* %indirect.goto.dest, [label %L1, label %L2, label %L3]
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L1:
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call void @foo()
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ret void
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L2:
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call void @bar()
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ret void
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L3:
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call void @baz()
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ret void
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}
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; A more complicated case: the condition is a select based on a comparison.
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2013-07-14 01:42:54 +00:00
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; CHECK-LABEL: @test_switch_cmp(
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2010-12-15 09:51:20 +00:00
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 %cond, label %L0, label %[[THREADED:[A-Za-z.0-9]+]]
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; CHECK: [[THREADED]]:
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; CHECK-NEXT: call void @quux
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; CHECK-NEXT: br label %L1
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define void @test_switch_cmp(i1 %cond, i32 %val, i8 %value) nounwind {
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entry:
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br i1 %cond, label %L0, label %L4
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L0:
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%val.phi = phi i32 [%val, %entry], [-1, %L4]
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%cmp = icmp slt i32 %val.phi, 0
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%expr = select i1 %cmp, i8 1, i8 %value
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switch i8 %expr, label %L3 [i8 1, label %L1 i8 2, label %L2]
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L1:
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call void @foo()
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ret void
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L2:
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call void @bar()
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ret void
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L3:
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call void @baz()
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ret void
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L4:
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call void @quux()
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br label %L0
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}
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2012-09-05 23:45:58 +00:00
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; Make sure the edge value of %0 from entry to L2 includes 0 and L3 is
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; reachable.
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; CHECK: test_switch_default
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; CHECK: entry:
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; CHECK: load
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2014-06-17 14:34:19 +00:00
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; CHECK: icmp
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2012-09-05 23:45:58 +00:00
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; CHECK: [[THREADED:[A-Za-z.0-9]+]]:
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; CHECK: store
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; CHECK: br
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; CHECK: L2:
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; CHECK: icmp
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define void @test_switch_default(i32* nocapture %status) nounwind {
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entry:
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%0 = load i32* %status, align 4
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switch i32 %0, label %L2 [
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i32 5061, label %L1
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i32 0, label %L2
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]
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L1:
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store i32 10025, i32* %status, align 4
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br label %L2
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L2:
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%1 = load i32* %status, align 4
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%cmp57.i = icmp eq i32 %1, 0
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br i1 %cmp57.i, label %L3, label %L4
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L3:
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store i32 10000, i32* %status, align 4
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br label %L4
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L4:
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ret void
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}
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JumpThreading: Turn a select instruction into branching if it allows to thread one half of the select.
This is a common pattern coming out of simplifycfg generating gross code.
a: ; preds = %entry
%sel = select i1 %cmp1, double %add, double 0.000000e+00
br label %b
b:
%cond5 = phi double [ %sel, %a ], [ %sub, %entry ]
%cmp6 = fcmp oeq double %cond5, 0.000000e+00
br i1 %cmp6, label %if.then, label %if.end
becomes
a:
br i1 %cmp1, label %b, label %if.then
b:
%cond5 = phi double [ %sub, %entry ], [ %add, %a ]
%cmp6 = fcmp oeq double %cond5, 0.000000e+00
br i1 %cmp6, label %if.then, label %if.end
Skipping block b completely if possible.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187880 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-07 10:29:38 +00:00
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define void @unfold1(double %x, double %y) nounwind {
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entry:
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%sub = fsub double %x, %y
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%cmp = fcmp ogt double %sub, 1.000000e+01
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br i1 %cmp, label %cond.end4, label %cond.false
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cond.false: ; preds = %entry
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%add = fadd double %x, %y
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%cmp1 = fcmp ogt double %add, 1.000000e+01
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%add. = select i1 %cmp1, double %add, double 0.000000e+00
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br label %cond.end4
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cond.end4: ; preds = %entry, %cond.false
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%cond5 = phi double [ %add., %cond.false ], [ %sub, %entry ]
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%cmp6 = fcmp oeq double %cond5, 0.000000e+00
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br i1 %cmp6, label %if.then, label %if.end
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if.then: ; preds = %cond.end4
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call void @foo()
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br label %if.end
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if.end: ; preds = %if.then, %cond.end4
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ret void
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; CHECK-LABEL: @unfold1
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; CHECK: br i1 %cmp, label %cond.end4, label %cond.false
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; CHECK: br i1 %cmp1, label %cond.end4, label %if.then
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; CHECK: br i1 %cmp6, label %if.then, label %if.end
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; CHECK: br label %if.end
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}
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define void @unfold2(i32 %x, i32 %y) nounwind {
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entry:
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%sub = sub nsw i32 %x, %y
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%cmp = icmp sgt i32 %sub, 10
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br i1 %cmp, label %cond.end4, label %cond.false
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cond.false: ; preds = %entry
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%add = add nsw i32 %x, %y
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%cmp1 = icmp sgt i32 %add, 10
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%add. = select i1 %cmp1, i32 0, i32 %add
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br label %cond.end4
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cond.end4: ; preds = %entry, %cond.false
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%cond5 = phi i32 [ %add., %cond.false ], [ %sub, %entry ]
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%cmp6 = icmp eq i32 %cond5, 0
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br i1 %cmp6, label %if.then, label %if.end
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if.then: ; preds = %cond.end4
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call void @foo()
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br label %if.end
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if.end: ; preds = %if.then, %cond.end4
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ret void
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; CHECK-LABEL: @unfold2
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; CHECK: br i1 %cmp, label %if.end, label %cond.false
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; CHECK: br i1 %cmp1, label %if.then, label %cond.end4
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; CHECK: br i1 %cmp6, label %if.then, label %if.end
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; CHECK: br label %if.end
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}
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