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; RUN: opt < %s -passes=tailcallelim -verify-dom-info -S | FileCheck %s
define i32 @test1_factorial(i32 %x) {
entry:
%tmp.1 = icmp sgt i32 %x, 0
br i1 %tmp.1, label %then, label %else
then:
%tmp.6 = add i32 %x, -1
%recurse = call i32 @test1_factorial( i32 %tmp.6 )
%accumulate = mul i32 %recurse, %x
ret i32 %accumulate
else:
ret i32 1
}
; CHECK-LABEL: define i32 @test1_factorial(
; CHECK: tailrecurse:
; CHECK: %accumulator.tr = phi i32 [ 1, %entry ], [ %accumulate, %then ]
; CHECK: then:
; CHECK-NOT: %recurse
; CHECK: %accumulate = mul i32 %accumulator.tr, %x.tr
; CHECK: else:
; CHECK: %accumulator.ret.tr = mul i32 %accumulator.tr, 1
; CHECK: ret i32 %accumulator.ret.tr
; This is a more aggressive form of accumulator recursion insertion, which
; requires noticing that X doesn't change as we perform the tailcall.
define i32 @test2_mul(i32 %x, i32 %y) {
entry:
%tmp.1 = icmp eq i32 %y, 0
br i1 %tmp.1, label %return, label %endif
endif:
%tmp.8 = add i32 %y, -1
%recurse = call i32 @test2_mul( i32 %x, i32 %tmp.8 )
%accumulate = add i32 %recurse, %x
ret i32 %accumulate
return:
ret i32 %x
}
; CHECK-LABEL: define i32 @test2_mul(
; CHECK: tailrecurse:
; CHECK: %accumulator.tr = phi i32 [ 0, %entry ], [ %accumulate, %endif ]
; CHECK: endif:
; CHECK-NOT: %recurse
; CHECK: %accumulate = add i32 %accumulator.tr, %x
; CHECK: return:
; CHECK: %accumulator.ret.tr = add i32 %accumulator.tr, %x
; CHECK: ret i32 %accumulator.ret.tr
define i64 @test3_fib(i64 %n) nounwind readnone {
entry:
switch i64 %n, label %bb1 [
i64 0, label %bb2
i64 1, label %bb2
]
bb1:
%0 = add i64 %n, -1
%recurse1 = tail call i64 @test3_fib(i64 %0) nounwind
%1 = add i64 %n, -2
%recurse2 = tail call i64 @test3_fib(i64 %1) nounwind
%accumulate = add nsw i64 %recurse2, %recurse1
ret i64 %accumulate
bb2:
ret i64 %n
}
; CHECK-LABEL: define i64 @test3_fib(
; CHECK: tailrecurse:
; CHECK: %accumulator.tr = phi i64 [ 0, %entry ], [ %accumulate, %bb1 ]
; CHECK: bb1:
; CHECK-NOT: %recurse2
; CHECK: %accumulate = add nsw i64 %accumulator.tr, %recurse1
; CHECK: bb2:
; CHECK: %accumulator.ret.tr = add nsw i64 %accumulator.tr, %n.tr
; CHECK: ret i64 %accumulator.ret.tr
define i32 @test4_base_case_call() local_unnamed_addr {
entry:
%base = call i32 @test4_helper()
switch i32 %base, label %sw.default [
i32 1, label %cleanup
i32 5, label %cleanup
i32 7, label %cleanup
]
sw.default:
%recurse = call i32 @test4_base_case_call()
%accumulate = add nsw i32 %recurse, 1
br label %cleanup
cleanup:
%retval.0 = phi i32 [ %accumulate, %sw.default ], [ %base, %entry ], [ %base, %entry ], [ %base, %entry ]
ret i32 %retval.0
}
declare i32 @test4_helper()
; CHECK-LABEL: define i32 @test4_base_case_call(
; CHECK: tailrecurse:
; CHECK: %accumulator.tr = phi i32 [ 0, %entry ], [ %accumulate, %sw.default ]
; CHECK: sw.default:
; CHECK-NOT: %recurse
; CHECK: %accumulate = add nsw i32 %accumulator.tr, 1
; CHECK: cleanup:
; CHECK: %accumulator.ret.tr = add nsw i32 %accumulator.tr, %base
; CHECK: ret i32 %accumulator.ret.tr
define i32 @test5_base_case_load(ptr nocapture %A, i32 %n) local_unnamed_addr {
entry:
%cmp = icmp eq i32 %n, 0
br i1 %cmp, label %if.then, label %if.end
if.then:
%base = load i32, ptr %A, align 4
ret i32 %base
if.end:
%idxprom = zext i32 %n to i64
%arrayidx1 = getelementptr inbounds i32, ptr %A, i64 %idxprom
%load = load i32, ptr %arrayidx1, align 4
%sub = add i32 %n, -1
%recurse = tail call i32 @test5_base_case_load(ptr %A, i32 %sub)
%accumulate = add i32 %recurse, %load
ret i32 %accumulate
}
; CHECK-LABEL: define i32 @test5_base_case_load(
; CHECK: tailrecurse:
; CHECK: %accumulator.tr = phi i32 [ 0, %entry ], [ %accumulate, %if.end ]
; CHECK: if.then:
; CHECK: %accumulator.ret.tr = add i32 %accumulator.tr, %base
; CHECK: ret i32 %accumulator.ret.tr
; CHECK: if.end:
; CHECK-NOT: %recurse
; CHECK: %accumulate = add i32 %accumulator.tr, %load
define i32 @test6_multiple_returns(i32 %x, i32 %y) local_unnamed_addr {
entry:
switch i32 %x, label %default [
i32 0, label %case0
i32 99, label %case99
]
case0:
%helper = call i32 @test6_helper()
ret i32 %helper
case99:
%sub1 = add i32 %x, -1
%recurse1 = call i32 @test6_multiple_returns(i32 %sub1, i32 %y)
ret i32 18
default:
%sub2 = add i32 %x, -1
%recurse2 = call i32 @test6_multiple_returns(i32 %sub2, i32 %y)
%accumulate = add i32 %recurse2, %y
ret i32 %accumulate
}
declare i32 @test6_helper()
; CHECK-LABEL: define i32 @test6_multiple_returns(
; CHECK: tailrecurse:
; CHECK: %accumulator.tr = phi i32 [ %accumulator.tr, %case99 ], [ 0, %entry ], [ %accumulate, %default ]
; CHECK: %ret.tr = phi i32 [ poison, %entry ], [ %current.ret.tr, %case99 ], [ %ret.tr, %default ]
; CHECK: %ret.known.tr = phi i1 [ false, %entry ], [ true, %case99 ], [ %ret.known.tr, %default ]
; CHECK: case0:
; CHECK: %accumulator.ret.tr2 = add i32 %accumulator.tr, %helper
; CHECK: %current.ret.tr1 = select i1 %ret.known.tr, i32 %ret.tr, i32 %accumulator.ret.tr2
; CHECK: case99:
; CHECK-NOT: %recurse
; CHECK: %accumulator.ret.tr = add i32 %accumulator.tr, 18
; CHECK: %current.ret.tr = select i1 %ret.known.tr, i32 %ret.tr, i32 %accumulator.ret.tr
; CHECK: default:
; CHECK-NOT: %recurse
; CHECK: %accumulate = add i32 %accumulator.tr, %y
; It is only safe to transform one accumulator per function, make sure we don't
; try to remove more.
define i32 @test7_multiple_accumulators(i32 %a) local_unnamed_addr {
entry:
%tobool = icmp eq i32 %a, 0
br i1 %tobool, label %return, label %if.end
if.end:
%and = and i32 %a, 1
%tobool1 = icmp eq i32 %and, 0
%sub = add nsw i32 %a, -1
br i1 %tobool1, label %if.end3, label %if.then2
if.then2:
%recurse1 = tail call i32 @test7_multiple_accumulators(i32 %sub)
%accumulate1 = add nsw i32 %recurse1, 1
br label %return
if.end3:
%recurse2 = tail call i32 @test7_multiple_accumulators(i32 %sub)
%accumulate2 = mul nsw i32 %recurse2, 2
br label %return
return:
%retval.0 = phi i32 [ %accumulate1, %if.then2 ], [ %accumulate2, %if.end3 ], [ 0, %entry ]
ret i32 %retval.0
}
; CHECK-LABEL: define i32 @test7_multiple_accumulators(
; CHECK: tailrecurse:
; CHECK: %accumulator.tr = phi i32 [ 0, %entry ], [ %accumulate1, %if.then2 ]
; CHECK: if.then2:
; CHECK-NOT: %recurse1
; CHECK: %accumulate1 = add nsw i32 %accumulator.tr, 1
; CHECK: if.end3:
; CHECK: %recurse2
; CHECK: %accumulator.ret.tr = add nsw i32 %accumulator.tr, %accumulate2
; CHECK: ret i32 %accumulator.ret.tr
; CHECK: return:
; CHECK: %accumulator.ret.tr1 = add nsw i32 %accumulator.tr, 0
; CHECK: ret i32 %accumulator.ret.tr1
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