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48 lines
1.4 KiB
LLVM
48 lines
1.4 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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; XFAIL: *
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; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep %ELIM
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; test1 - Eliminating the casts in this testcase (by narrowing the AND
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; operation) allows instcombine to realize the function always returns false.
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;
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bool %test1(int %A, int %B) {
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%C1 = setlt int %A, %B
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%ELIM1 = cast bool %C1 to uint
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%C2 = setgt int %A, %B
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%ELIM2 = cast bool %C2 to uint
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%C3 = and uint %ELIM1, %ELIM2
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%ELIM3 = cast uint %C3 to bool
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ret bool %ELIM3
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}
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; See if we can eliminate the shifts...
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int %test2(int %B) {
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%ELIM1 = shl int %B, ubyte 31
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%ELIM2 = shr int %ELIM1, ubyte 31
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%inc = add int %ELIM2, 1 ; == xor int %B, 1
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ret int %inc
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}
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; Reduce down to a single XOR
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int %test3(int %B) {
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%ELIMinc = and int %B, 1
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%tmp.5 = xor int %ELIMinc, 1
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%ELIM7 = and int %B, -2
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%tmp.8 = or int %tmp.5, %ELIM7
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ret int %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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int %test4(int %B) {
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%ELIM3 = shl int %B, ubyte 31
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%ELIM4 = shr int %ELIM3, ubyte 31
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%inc = add int %ELIM4, 1
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%ELIM5 = and int %inc, 1
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%ELIM7 = and int %B, -2
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%tmp.8 = or int %ELIM5, %ELIM7
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ret int %tmp.8
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}
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