test/Transforms/InstCombine/shift.ll

; This test makes sure that these instructions are properly eliminated.
;

; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep sh

implementation

int %test1(int %A) {
	%B = shl int %A, ubyte 0
	ret int %B
}

int %test2(ubyte %A) {
	%B = shl int 0, ubyte %A
	ret int %B
}

int %test3(int %A) {
	%B = shr int %A, ubyte 0
	ret int %B
}

int %test4(ubyte %A) {
	%B = shr int 0, ubyte %A
	ret int %B
}

uint %test5(uint %A) {
	%B = shr uint %A, ubyte 32  ;; shift all bits out
	ret uint %B
}

uint %test5a(uint %A) {
	%B = shl uint %A, ubyte 32  ;; shift all bits out
	ret uint %B
}

uint %test6(uint %A) {
	%B = shl uint %A, ubyte 1   ;; convert to an mul instruction
	%C = mul uint %B, 3
	ret uint %C
}

int %test7(ubyte %A) {
	%B = shr int -1, ubyte %A   ;; Always equal to -1
	ret int %B
}

ubyte %test8(ubyte %A) {              ;; (A << 5) << 3 === A << 8 == 0
	%B = shl ubyte %A, ubyte 5
	%C = shl ubyte %B, ubyte 3
	ret ubyte %C
}

ubyte %test9(ubyte %A) {              ;; (A << 7) >> 7 === A & 1
	%B = shl ubyte %A, ubyte 7
	%C = shr ubyte %B, ubyte 7
	ret ubyte %C
}

ubyte %test10(ubyte %A) {              ;; (A >> 7) << 7 === A & 128
	%B = shr ubyte %A, ubyte 7
	%C = shl ubyte %B, ubyte 7
	ret ubyte %C
}

ubyte %test11(ubyte %A) {              ;; (A >> 3) << 4 === (A & 0x1F) << 1
	%a = mul ubyte %A, 3
	%B = shr ubyte %a, ubyte 3
	%C = shl ubyte %B, ubyte 4
	ret ubyte %C
}

int %test12(int %A) {
        %B = shr int %A, ubyte 8    ;; (A >> 8) << 8 === A & -256
        %C = shl int %B, ubyte 8
        ret int %C
}

sbyte %test13(sbyte %A) {           ;; (A >> 3) << 4 === (A & -8) * 2
	%a = mul sbyte %A, 3
	%B = shr sbyte %a, ubyte 3
	%C = shl sbyte %B, ubyte 4
	ret sbyte %C
}

uint %test14(uint %A) {
	%B = shr uint %A, ubyte 4
	%C = or uint %B, 1234
	%D = shl uint %C, ubyte 4   ;; D = ((B | 1234) << 4) === ((B << 4)|(1234 << 4)
	ret uint %D
}
uint %test14a(uint %A) {
	%B = shl uint %A, ubyte 4
	%C = and uint %B, 1234
	%D = shr uint %C, ubyte 4   ;; D = ((B | 1234) << 4) === ((B << 4)|(1234 << 4)
	ret uint %D
}