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