75 lines
1.9 KiB
LLVM
75 lines
1.9 KiB
LLVM
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; RUN: opt < %s -tailcallelim -S | FileCheck %s
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define i32 @test1_factorial(i32 %x) {
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entry:
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%tmp.1 = icmp sgt i32 %x, 0 ; <i1> [#uses=1]
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br i1 %tmp.1, label %then, label %else
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then: ; preds = %entry
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%tmp.6 = add i32 %x, -1 ; <i32> [#uses=1]
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%tmp.4 = call i32 @test1_factorial( i32 %tmp.6 ) ; <i32> [#uses=1]
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%tmp.7 = mul i32 %tmp.4, %x ; <i32> [#uses=1]
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ret i32 %tmp.7
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else: ; preds = %entry
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ret i32 1
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}
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; CHECK: define i32 @test1_factorial
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; CHECK: phi i32
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; CHECK-NOT: call i32
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; CHECK: else:
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; This is a more aggressive form of accumulator recursion insertion, which
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; requires noticing that X doesn't change as we perform the tailcall.
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define i32 @test2_mul(i32 %x, i32 %y) {
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entry:
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%tmp.1 = icmp eq i32 %y, 0 ; <i1> [#uses=1]
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br i1 %tmp.1, label %return, label %endif
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endif: ; preds = %entry
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%tmp.8 = add i32 %y, -1 ; <i32> [#uses=1]
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%tmp.5 = call i32 @test2_mul( i32 %x, i32 %tmp.8 ) ; <i32> [#uses=1]
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%tmp.9 = add i32 %tmp.5, %x ; <i32> [#uses=1]
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ret i32 %tmp.9
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return: ; preds = %entry
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ret i32 %x
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}
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; CHECK: define i32 @test2_mul
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; CHECK: phi i32
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; CHECK-NOT: call i32
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; CHECK: return:
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define i64 @test3_fib(i64 %n) nounwind readnone {
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; CHECK: @test3_fib
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entry:
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; CHECK: tailrecurse:
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; CHECK: %accumulator.tr = phi i64 [ %n, %entry ], [ %3, %bb1 ]
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; CHECK: %n.tr = phi i64 [ %n, %entry ], [ %2, %bb1 ]
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switch i64 %n, label %bb1 [
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; CHECK: switch i64 %n.tr, label %bb1 [
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i64 0, label %bb2
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i64 1, label %bb2
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]
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bb1:
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; CHECK: bb1:
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%0 = add i64 %n, -1
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; CHECK: %0 = add i64 %n.tr, -1
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%1 = tail call i64 @test3_fib(i64 %0) nounwind
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; CHECK: %1 = tail call i64 @test3_fib(i64 %0)
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%2 = add i64 %n, -2
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; CHECK: %2 = add i64 %n.tr, -2
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%3 = tail call i64 @test3_fib(i64 %2) nounwind
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; CHECK-NOT: tail call i64 @test3_fib
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%4 = add nsw i64 %3, %1
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; CHECK: add nsw i64 %accumulator.tr, %1
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ret i64 %4
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; CHECK: br label %tailrecurse
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bb2:
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; CHECK: bb2:
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ret i64 %n
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; CHECK: ret i64 %accumulator.tr
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}
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