1 ; RUN: opt < %s -tailcallelim -S | FileCheck %s 2 ; RUN: opt < %s -passes=tailcallelim -S | FileCheck %s 3 4 define i32 @test1_factorial(i32 %x) { 5 entry: 6 %tmp.1 = icmp sgt i32 %x, 0 ; <i1> [#uses=1] 7 br i1 %tmp.1, label %then, label %else 8 then: ; preds = %entry 9 %tmp.6 = add i32 %x, -1 ; <i32> [#uses=1] 10 %tmp.4 = call i32 @test1_factorial( i32 %tmp.6 ) ; <i32> [#uses=1] 11 %tmp.7 = mul i32 %tmp.4, %x ; <i32> [#uses=1] 12 ret i32 %tmp.7 13 else: ; preds = %entry 14 ret i32 1 15 } 16 17 ; CHECK-LABEL: define i32 @test1_factorial( 18 ; CHECK: phi i32 19 ; CHECK-NOT: call i32 20 ; CHECK: else: 21 22 ; This is a more aggressive form of accumulator recursion insertion, which 23 ; requires noticing that X doesn't change as we perform the tailcall. 24 25 define i32 @test2_mul(i32 %x, i32 %y) { 26 entry: 27 %tmp.1 = icmp eq i32 %y, 0 ; <i1> [#uses=1] 28 br i1 %tmp.1, label %return, label %endif 29 endif: ; preds = %entry 30 %tmp.8 = add i32 %y, -1 ; <i32> [#uses=1] 31 %tmp.5 = call i32 @test2_mul( i32 %x, i32 %tmp.8 ) ; <i32> [#uses=1] 32 %tmp.9 = add i32 %tmp.5, %x ; <i32> [#uses=1] 33 ret i32 %tmp.9 34 return: ; preds = %entry 35 ret i32 %x 36 } 37 38 ; CHECK-LABEL: define i32 @test2_mul( 39 ; CHECK: phi i32 40 ; CHECK-NOT: call i32 41 ; CHECK: return: 42 43 44 define i64 @test3_fib(i64 %n) nounwind readnone { 45 ; CHECK-LABEL: @test3_fib( 46 entry: 47 ; CHECK: tailrecurse: 48 ; CHECK: %accumulator.tr = phi i64 [ %n, %entry ], [ %3, %bb1 ] 49 ; CHECK: %n.tr = phi i64 [ %n, %entry ], [ %2, %bb1 ] 50 switch i64 %n, label %bb1 [ 51 ; CHECK: switch i64 %n.tr, label %bb1 [ 52 i64 0, label %bb2 53 i64 1, label %bb2 54 ] 55 56 bb1: 57 ; CHECK: bb1: 58 %0 = add i64 %n, -1 59 ; CHECK: %0 = add i64 %n.tr, -1 60 %1 = tail call i64 @test3_fib(i64 %0) nounwind 61 ; CHECK: %1 = tail call i64 @test3_fib(i64 %0) 62 %2 = add i64 %n, -2 63 ; CHECK: %2 = add i64 %n.tr, -2 64 %3 = tail call i64 @test3_fib(i64 %2) nounwind 65 ; CHECK-NOT: tail call i64 @test3_fib 66 %4 = add nsw i64 %3, %1 67 ; CHECK: add nsw i64 %accumulator.tr, %1 68 ret i64 %4 69 ; CHECK: br label %tailrecurse 70 71 bb2: 72 ; CHECK: bb2: 73 ret i64 %n 74 ; CHECK: ret i64 %accumulator.tr 75 } 76
