| ; This test makes sure that these instructions are properly eliminated. |
| ; |
| ; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep phi |
| ; END. |
| |
| define i32 @test1(i32 %A, i1 %b) { |
| BB0: |
| br i1 %b, label %BB1, label %BB2 |
| |
| BB1: ; preds = %BB0 |
| ; Combine away one argument PHI nodes |
| %B = phi i32 [ %A, %BB0 ] ; <i32> [#uses=1] |
| ret i32 %B |
| |
| BB2: ; preds = %BB0 |
| ret i32 %A |
| } |
| |
| define i32 @test2(i32 %A, i1 %b) { |
| BB0: |
| br i1 %b, label %BB1, label %BB2 |
| |
| BB1: ; preds = %BB0 |
| br label %BB2 |
| |
| BB2: ; preds = %BB1, %BB0 |
| ; Combine away PHI nodes with same values |
| %B = phi i32 [ %A, %BB0 ], [ %A, %BB1 ] ; <i32> [#uses=1] |
| ret i32 %B |
| } |
| |
| define i32 @test3(i32 %A, i1 %b) { |
| BB0: |
| br label %Loop |
| |
| Loop: ; preds = %Loop, %BB0 |
| ; PHI has same value always. |
| %B = phi i32 [ %A, %BB0 ], [ %B, %Loop ] ; <i32> [#uses=2] |
| br i1 %b, label %Loop, label %Exit |
| |
| Exit: ; preds = %Loop |
| ret i32 %B |
| } |
| |
| define i32 @test4(i1 %b) { |
| BB0: |
| ; Loop is unreachable |
| ret i32 7 |
| |
| Loop: ; preds = %L2, %Loop |
| ; PHI has same value always. |
| %B = phi i32 [ %B, %L2 ], [ %B, %Loop ] ; <i32> [#uses=2] |
| br i1 %b, label %L2, label %Loop |
| |
| L2: ; preds = %Loop |
| br label %Loop |
| } |
| |
| define i32 @test5(i32 %A, i1 %b) { |
| BB0: |
| br label %Loop |
| |
| Loop: ; preds = %Loop, %BB0 |
| ; PHI has same value always. |
| %B = phi i32 [ %A, %BB0 ], [ undef, %Loop ] ; <i32> [#uses=1] |
| br i1 %b, label %Loop, label %Exit |
| |
| Exit: ; preds = %Loop |
| ret i32 %B |
| } |
| |
| define i32 @test6(i32 %A, i1 %b) { |
| BB0: |
| %X = bitcast i32 %A to i32 ; <i32> [#uses=1] |
| br i1 %b, label %BB1, label %BB2 |
| |
| BB1: ; preds = %BB0 |
| %Y = bitcast i32 %A to i32 ; <i32> [#uses=1] |
| br label %BB2 |
| |
| BB2: ; preds = %BB1, %BB0 |
| ;; Suck casts into phi |
| %B = phi i32 [ %X, %BB0 ], [ %Y, %BB1 ] ; <i32> [#uses=1] |
| ret i32 %B |
| } |
| |
| define i32 @test7(i32 %A, i1 %b) { |
| BB0: |
| br label %Loop |
| |
| Loop: ; preds = %Loop, %BB0 |
| ; PHI is dead. |
| %B = phi i32 [ %A, %BB0 ], [ %C, %Loop ] ; <i32> [#uses=1] |
| %C = add i32 %B, 123 ; <i32> [#uses=1] |
| br i1 %b, label %Loop, label %Exit |
| |
| Exit: ; preds = %Loop |
| ret i32 0 |
| } |
| |
| |