1; The unify-function-exit-nodes pass often makes basic blocks that just contain 2; a PHI node and a return. Make sure the simplify cfg can straighten out this 3; important case. This is basically the most trivial form of tail-duplication. 4 5; RUN: opt < %s -simplifycfg -S | \ 6; RUN: not grep "br label" 7 8define i32 @test(i1 %B, i32 %A, i32 %B.upgrd.1) { 9 br i1 %B, label %T, label %F 10T: ; preds = %0 11 br label %ret 12F: ; preds = %0 13 br label %ret 14ret: ; preds = %F, %T 15 %X = phi i32 [ %A, %F ], [ %B.upgrd.1, %T ] ; <i32> [#uses=1] 16 ret i32 %X 17} 18 19 20; Make sure it's willing to move unconditional branches to return instructions 21; as well, even if the return block is shared and the source blocks are 22; non-empty. 23define i32 @test2(i1 %B, i32 %A, i32 %B.upgrd.2) { 24 br i1 %B, label %T, label %F 25T: ; preds = %0 26 call i32 @test( i1 true, i32 5, i32 8 ) ; <i32>:1 [#uses=0] 27 br label %ret 28F: ; preds = %0 29 call i32 @test( i1 true, i32 5, i32 8 ) ; <i32>:2 [#uses=0] 30 br label %ret 31ret: ; preds = %F, %T 32 ret i32 %A 33} 34