forked from OSchip/llvm-project
27 lines
1.1 KiB
LLVM
27 lines
1.1 KiB
LLVM
; This file contains various testcases that require tracking whether bits are
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; set or cleared by various instructions.
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; RUN: llvm-as < %s | opt -instcombine -instcombine | llvm-dis |\
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; RUN: not grep %ELIM
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; Reduce down to a single XOR
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define i32 @test3(i32 %B) {
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%ELIMinc = and i32 %B, 1 ; <i32> [#uses=1]
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%tmp.5 = xor i32 %ELIMinc, 1 ; <i32> [#uses=1]
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%ELIM7 = and i32 %B, -2 ; <i32> [#uses=1]
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%tmp.8 = or i32 %tmp.5, %ELIM7 ; <i32> [#uses=1]
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ret i32 %tmp.8
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}
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; Finally, a bigger case where we chain things together. This corresponds to
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; incrementing a single-bit bitfield, which should become just an xor.
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define i32 @test4(i32 %B) {
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%ELIM3 = shl i32 %B, 31 ; <i32> [#uses=1]
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%ELIM4 = ashr i32 %ELIM3, 31 ; <i32> [#uses=1]
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%inc = add i32 %ELIM4, 1 ; <i32> [#uses=1]
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%ELIM5 = and i32 %inc, 1 ; <i32> [#uses=1]
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%ELIM7 = and i32 %B, -2 ; <i32> [#uses=1]
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%tmp.8 = or i32 %ELIM5, %ELIM7 ; <i32> [#uses=1]
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ret i32 %tmp.8
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}
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