; RUN: opt < %s -tailcallelim -S | FileCheck %s | |
define i32 @test1_factorial(i32 %x) { | |
entry: | |
%tmp.1 = icmp sgt i32 %x, 0 ; <i1> [#uses=1] | |
br i1 %tmp.1, label %then, label %else | |
then: ; preds = %entry | |
%tmp.6 = add i32 %x, -1 ; <i32> [#uses=1] | |
%tmp.4 = call i32 @test1_factorial( i32 %tmp.6 ) ; <i32> [#uses=1] | |
%tmp.7 = mul i32 %tmp.4, %x ; <i32> [#uses=1] | |
ret i32 %tmp.7 | |
else: ; preds = %entry | |
ret i32 1 | |
} | |
; CHECK: define i32 @test1_factorial | |
; CHECK: phi i32 | |
; CHECK-NOT: call i32 | |
; CHECK: else: | |
; 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 ; <i1> [#uses=1] | |
br i1 %tmp.1, label %return, label %endif | |
endif: ; preds = %entry | |
%tmp.8 = add i32 %y, -1 ; <i32> [#uses=1] | |
%tmp.5 = call i32 @test2_mul( i32 %x, i32 %tmp.8 ) ; <i32> [#uses=1] | |
%tmp.9 = add i32 %tmp.5, %x ; <i32> [#uses=1] | |
ret i32 %tmp.9 | |
return: ; preds = %entry | |
ret i32 %x | |
} | |
; CHECK: define i32 @test2_mul | |
; CHECK: phi i32 | |
; CHECK-NOT: call i32 | |
; CHECK: return: | |
define i64 @test3_fib(i64 %n) nounwind readnone { | |
; CHECK: @test3_fib | |
entry: | |
; CHECK: tailrecurse: | |
; CHECK: %accumulator.tr = phi i64 [ %n, %entry ], [ %3, %bb1 ] | |
; CHECK: %n.tr = phi i64 [ %n, %entry ], [ %2, %bb1 ] | |
switch i64 %n, label %bb1 [ | |
; CHECK: switch i64 %n.tr, label %bb1 [ | |
i64 0, label %bb2 | |
i64 1, label %bb2 | |
] | |
bb1: | |
; CHECK: bb1: | |
%0 = add i64 %n, -1 | |
; CHECK: %0 = add i64 %n.tr, -1 | |
%1 = tail call i64 @test3_fib(i64 %0) nounwind | |
; CHECK: %1 = tail call i64 @test3_fib(i64 %0) | |
%2 = add i64 %n, -2 | |
; CHECK: %2 = add i64 %n.tr, -2 | |
%3 = tail call i64 @test3_fib(i64 %2) nounwind | |
; CHECK-NOT: tail call i64 @test3_fib | |
%4 = add nsw i64 %3, %1 | |
; CHECK: add nsw i64 %accumulator.tr, %1 | |
ret i64 %4 | |
; CHECK: br label %tailrecurse | |
bb2: | |
; CHECK: bb2: | |
ret i64 %n | |
; CHECK: ret i64 %accumulator.tr | |
} |