llvm-6502/test/Transforms/InstSimplify/compare.ll
2014-01-24 17:09:53 +00:00

760 lines
17 KiB
LLVM

; RUN: opt < %s -instsimplify -S | FileCheck %s
target datalayout = "p:32:32"
define i1 @ptrtoint() {
; CHECK-LABEL: @ptrtoint(
%a = alloca i8
%tmp = ptrtoint i8* %a to i32
%r = icmp eq i32 %tmp, 0
ret i1 %r
; CHECK: ret i1 false
}
define i1 @bitcast() {
; CHECK-LABEL: @bitcast(
%a = alloca i32
%b = alloca i64
%x = bitcast i32* %a to i8*
%y = bitcast i64* %b to i8*
%cmp = icmp eq i8* %x, %y
ret i1 %cmp
; CHECK-NEXT: ret i1 false
}
define i1 @gep() {
; CHECK-LABEL: @gep(
%a = alloca [3 x i8], align 8
%x = getelementptr inbounds [3 x i8]* %a, i32 0, i32 0
%cmp = icmp eq i8* %x, null
ret i1 %cmp
; CHECK-NEXT: ret i1 false
}
define i1 @gep2() {
; CHECK-LABEL: @gep2(
%a = alloca [3 x i8], align 8
%x = getelementptr inbounds [3 x i8]* %a, i32 0, i32 0
%y = getelementptr inbounds [3 x i8]* %a, i32 0, i32 0
%cmp = icmp eq i8* %x, %y
ret i1 %cmp
; CHECK-NEXT: ret i1 true
}
; PR11238
%gept = type { i32, i32 }
@gepy = global %gept zeroinitializer, align 8
@gepz = extern_weak global %gept
define i1 @gep3() {
; CHECK-LABEL: @gep3(
%x = alloca %gept, align 8
%a = getelementptr %gept* %x, i64 0, i32 0
%b = getelementptr %gept* %x, i64 0, i32 1
%equal = icmp eq i32* %a, %b
ret i1 %equal
; CHECK-NEXT: ret i1 false
}
define i1 @gep4() {
; CHECK-LABEL: @gep4(
%x = alloca %gept, align 8
%a = getelementptr %gept* @gepy, i64 0, i32 0
%b = getelementptr %gept* @gepy, i64 0, i32 1
%equal = icmp eq i32* %a, %b
ret i1 %equal
; CHECK-NEXT: ret i1 false
}
define i1 @gep5() {
; CHECK-LABEL: @gep5(
%x = alloca %gept, align 8
%a = getelementptr inbounds %gept* %x, i64 0, i32 1
%b = getelementptr %gept* @gepy, i64 0, i32 0
%equal = icmp eq i32* %a, %b
ret i1 %equal
; CHECK-NEXT: ret i1 false
}
define i1 @gep6(%gept* %x) {
; Same as @gep3 but potentially null.
; CHECK-LABEL: @gep6(
%a = getelementptr %gept* %x, i64 0, i32 0
%b = getelementptr %gept* %x, i64 0, i32 1
%equal = icmp eq i32* %a, %b
ret i1 %equal
; CHECK-NEXT: ret i1 false
}
define i1 @gep7(%gept* %x) {
; CHECK-LABEL: @gep7(
%a = getelementptr %gept* %x, i64 0, i32 0
%b = getelementptr %gept* @gepz, i64 0, i32 0
%equal = icmp eq i32* %a, %b
ret i1 %equal
; CHECK: ret i1 %equal
}
define i1 @gep8(%gept* %x) {
; CHECK-LABEL: @gep8(
%a = getelementptr %gept* %x, i32 1
%b = getelementptr %gept* %x, i32 -1
%equal = icmp ugt %gept* %a, %b
ret i1 %equal
; CHECK: ret i1 %equal
}
define i1 @gep9(i8* %ptr) {
; CHECK-LABEL: @gep9(
; CHECK-NOT: ret
; CHECK: ret i1 true
entry:
%first1 = getelementptr inbounds i8* %ptr, i32 0
%first2 = getelementptr inbounds i8* %first1, i32 1
%first3 = getelementptr inbounds i8* %first2, i32 2
%first4 = getelementptr inbounds i8* %first3, i32 4
%last1 = getelementptr inbounds i8* %first2, i32 48
%last2 = getelementptr inbounds i8* %last1, i32 8
%last3 = getelementptr inbounds i8* %last2, i32 -4
%last4 = getelementptr inbounds i8* %last3, i32 -4
%first.int = ptrtoint i8* %first4 to i32
%last.int = ptrtoint i8* %last4 to i32
%cmp = icmp ne i32 %last.int, %first.int
ret i1 %cmp
}
define i1 @gep10(i8* %ptr) {
; CHECK-LABEL: @gep10(
; CHECK-NOT: ret
; CHECK: ret i1 true
entry:
%first1 = getelementptr inbounds i8* %ptr, i32 -2
%first2 = getelementptr inbounds i8* %first1, i32 44
%last1 = getelementptr inbounds i8* %ptr, i32 48
%last2 = getelementptr inbounds i8* %last1, i32 -6
%first.int = ptrtoint i8* %first2 to i32
%last.int = ptrtoint i8* %last2 to i32
%cmp = icmp eq i32 %last.int, %first.int
ret i1 %cmp
}
define i1 @gep11(i8* %ptr) {
; CHECK-LABEL: @gep11(
; CHECK-NOT: ret
; CHECK: ret i1 true
entry:
%first1 = getelementptr inbounds i8* %ptr, i32 -2
%last1 = getelementptr inbounds i8* %ptr, i32 48
%last2 = getelementptr inbounds i8* %last1, i32 -6
%cmp = icmp ult i8* %first1, %last2
ret i1 %cmp
}
define i1 @gep12(i8* %ptr) {
; CHECK-LABEL: @gep12(
; CHECK-NOT: ret
; CHECK: ret i1 %cmp
entry:
%first1 = getelementptr inbounds i8* %ptr, i32 -2
%last1 = getelementptr inbounds i8* %ptr, i32 48
%last2 = getelementptr inbounds i8* %last1, i32 -6
%cmp = icmp slt i8* %first1, %last2
ret i1 %cmp
}
define i1 @gep13(i8* %ptr) {
; CHECK-LABEL: @gep13(
; We can prove this GEP is non-null because it is inbounds.
%x = getelementptr inbounds i8* %ptr, i32 1
%cmp = icmp eq i8* %x, null
ret i1 %cmp
; CHECK-NEXT: ret i1 false
}
define i1 @gep14({ {}, i8 }* %ptr) {
; CHECK-LABEL: @gep14(
; We can't simplify this because the offset of one in the GEP actually doesn't
; move the pointer.
%x = getelementptr inbounds { {}, i8 }* %ptr, i32 0, i32 1
%cmp = icmp eq i8* %x, null
ret i1 %cmp
; CHECK-NOT: ret i1 false
}
define i1 @gep15({ {}, [4 x {i8, i8}]}* %ptr, i32 %y) {
; CHECK-LABEL: @gep15(
; We can prove this GEP is non-null even though there is a user value, as we
; would necessarily violate inbounds on one side or the other.
%x = getelementptr inbounds { {}, [4 x {i8, i8}]}* %ptr, i32 0, i32 1, i32 %y, i32 1
%cmp = icmp eq i8* %x, null
ret i1 %cmp
; CHECK-NEXT: ret i1 false
}
define i1 @gep16(i8* %ptr, i32 %a) {
; CHECK-LABEL: @gep16(
; We can prove this GEP is non-null because it is inbounds and because we know
; %b is non-zero even though we don't know its value.
%b = or i32 %a, 1
%x = getelementptr inbounds i8* %ptr, i32 %b
%cmp = icmp eq i8* %x, null
ret i1 %cmp
; CHECK-NEXT: ret i1 false
}
define i1 @zext(i32 %x) {
; CHECK-LABEL: @zext(
%e1 = zext i32 %x to i64
%e2 = zext i32 %x to i64
%r = icmp eq i64 %e1, %e2
ret i1 %r
; CHECK: ret i1 true
}
define i1 @zext2(i1 %x) {
; CHECK-LABEL: @zext2(
%e = zext i1 %x to i32
%c = icmp ne i32 %e, 0
ret i1 %c
; CHECK: ret i1 %x
}
define i1 @zext3() {
; CHECK-LABEL: @zext3(
%e = zext i1 1 to i32
%c = icmp ne i32 %e, 0
ret i1 %c
; CHECK: ret i1 true
}
define i1 @sext(i32 %x) {
; CHECK-LABEL: @sext(
%e1 = sext i32 %x to i64
%e2 = sext i32 %x to i64
%r = icmp eq i64 %e1, %e2
ret i1 %r
; CHECK: ret i1 true
}
define i1 @sext2(i1 %x) {
; CHECK-LABEL: @sext2(
%e = sext i1 %x to i32
%c = icmp ne i32 %e, 0
ret i1 %c
; CHECK: ret i1 %x
}
define i1 @sext3() {
; CHECK-LABEL: @sext3(
%e = sext i1 1 to i32
%c = icmp ne i32 %e, 0
ret i1 %c
; CHECK: ret i1 true
}
define i1 @add(i32 %x, i32 %y) {
; CHECK-LABEL: @add(
%l = lshr i32 %x, 1
%q = lshr i32 %y, 1
%r = or i32 %q, 1
%s = add i32 %l, %r
%c = icmp eq i32 %s, 0
ret i1 %c
; CHECK: ret i1 false
}
define i1 @add2(i8 %x, i8 %y) {
; CHECK-LABEL: @add2(
%l = or i8 %x, 128
%r = or i8 %y, 129
%s = add i8 %l, %r
%c = icmp eq i8 %s, 0
ret i1 %c
; CHECK: ret i1 false
}
define i1 @add3(i8 %x, i8 %y) {
; CHECK-LABEL: @add3(
%l = zext i8 %x to i32
%r = zext i8 %y to i32
%s = add i32 %l, %r
%c = icmp eq i32 %s, 0
ret i1 %c
; CHECK: ret i1 %c
}
define i1 @add4(i32 %x, i32 %y) {
; CHECK-LABEL: @add4(
%z = add nsw i32 %y, 1
%s1 = add nsw i32 %x, %y
%s2 = add nsw i32 %x, %z
%c = icmp slt i32 %s1, %s2
ret i1 %c
; CHECK: ret i1 true
}
define i1 @add5(i32 %x, i32 %y) {
; CHECK-LABEL: @add5(
%z = add nuw i32 %y, 1
%s1 = add nuw i32 %x, %z
%s2 = add nuw i32 %x, %y
%c = icmp ugt i32 %s1, %s2
ret i1 %c
; CHECK: ret i1 true
}
define i1 @add6(i64 %A, i64 %B) {
; CHECK-LABEL: @add6(
%s1 = add i64 %A, %B
%s2 = add i64 %B, %A
%cmp = icmp eq i64 %s1, %s2
ret i1 %cmp
; CHECK: ret i1 true
}
define i1 @addpowtwo(i32 %x, i32 %y) {
; CHECK-LABEL: @addpowtwo(
%l = lshr i32 %x, 1
%r = shl i32 1, %y
%s = add i32 %l, %r
%c = icmp eq i32 %s, 0
ret i1 %c
; CHECK: ret i1 false
}
define i1 @or(i32 %x) {
; CHECK-LABEL: @or(
%o = or i32 %x, 1
%c = icmp eq i32 %o, 0
ret i1 %c
; CHECK: ret i1 false
}
define i1 @shl(i32 %x) {
; CHECK-LABEL: @shl(
%s = shl i32 1, %x
%c = icmp eq i32 %s, 0
ret i1 %c
; CHECK: ret i1 false
}
define i1 @lshr1(i32 %x) {
; CHECK-LABEL: @lshr1(
%s = lshr i32 -1, %x
%c = icmp eq i32 %s, 0
ret i1 %c
; CHECK: ret i1 false
}
define i1 @lshr2(i32 %x) {
; CHECK-LABEL: @lshr2(
%s = lshr i32 %x, 30
%c = icmp ugt i32 %s, 8
ret i1 %c
; CHECK: ret i1 false
}
define i1 @lshr3(i32 %x) {
; CHECK-LABEL: @lshr3(
%s = lshr i32 %x, %x
%c = icmp eq i32 %s, 0
ret i1 %c
; CHECK: ret i1 true
}
define i1 @ashr1(i32 %x) {
; CHECK-LABEL: @ashr1(
%s = ashr i32 -1, %x
%c = icmp eq i32 %s, 0
ret i1 %c
; CHECK: ret i1 false
}
define i1 @ashr2(i32 %x) {
; CHECK-LABEL: @ashr2(
%s = ashr i32 %x, 30
%c = icmp slt i32 %s, -5
ret i1 %c
; CHECK: ret i1 false
}
define i1 @ashr3(i32 %x) {
; CHECK-LABEL: @ashr3(
%s = ashr i32 %x, %x
%c = icmp eq i32 %s, 0
ret i1 %c
; CHECK: ret i1 true
}
define i1 @select1(i1 %cond) {
; CHECK-LABEL: @select1(
%s = select i1 %cond, i32 1, i32 0
%c = icmp eq i32 %s, 1
ret i1 %c
; CHECK: ret i1 %cond
}
define i1 @select2(i1 %cond) {
; CHECK-LABEL: @select2(
%x = zext i1 %cond to i32
%s = select i1 %cond, i32 %x, i32 0
%c = icmp ne i32 %s, 0
ret i1 %c
; CHECK: ret i1 %cond
}
define i1 @select3(i1 %cond) {
; CHECK-LABEL: @select3(
%x = zext i1 %cond to i32
%s = select i1 %cond, i32 1, i32 %x
%c = icmp ne i32 %s, 0
ret i1 %c
; CHECK: ret i1 %cond
}
define i1 @select4(i1 %cond) {
; CHECK-LABEL: @select4(
%invert = xor i1 %cond, 1
%s = select i1 %invert, i32 0, i32 1
%c = icmp ne i32 %s, 0
ret i1 %c
; CHECK: ret i1 %cond
}
define i1 @select5(i32 %x) {
; CHECK-LABEL: @select5(
%c = icmp eq i32 %x, 0
%s = select i1 %c, i32 1, i32 %x
%c2 = icmp eq i32 %s, 0
ret i1 %c2
; CHECK: ret i1 false
}
define i1 @select6(i32 %x) {
; CHECK-LABEL: @select6(
%c = icmp sgt i32 %x, 0
%s = select i1 %c, i32 %x, i32 4
%c2 = icmp eq i32 %s, 0
ret i1 %c2
; CHECK: ret i1 %c2
}
define i1 @urem1(i32 %X, i32 %Y) {
; CHECK-LABEL: @urem1(
%A = urem i32 %X, %Y
%B = icmp ult i32 %A, %Y
ret i1 %B
; CHECK: ret i1 true
}
define i1 @urem2(i32 %X, i32 %Y) {
; CHECK-LABEL: @urem2(
%A = urem i32 %X, %Y
%B = icmp eq i32 %A, %Y
ret i1 %B
; CHECK: ret i1 false
}
define i1 @urem3(i32 %X) {
; CHECK-LABEL: @urem3(
%A = urem i32 %X, 10
%B = icmp ult i32 %A, 15
ret i1 %B
; CHECK: ret i1 true
}
define i1 @urem4(i32 %X) {
; CHECK-LABEL: @urem4(
%A = urem i32 %X, 15
%B = icmp ult i32 %A, 10
ret i1 %B
; CHECK: ret i1 %B
}
define i1 @urem5(i16 %X, i32 %Y) {
; CHECK-LABEL: @urem5(
%A = zext i16 %X to i32
%B = urem i32 %A, %Y
%C = icmp slt i32 %B, %Y
ret i1 %C
; CHECK-NOT: ret i1 true
}
define i1 @urem6(i32 %X, i32 %Y) {
; CHECK-LABEL: @urem6(
%A = urem i32 %X, %Y
%B = icmp ugt i32 %Y, %A
ret i1 %B
; CHECK: ret i1 true
}
define i1 @urem7(i32 %X) {
; CHECK-LABEL: @urem7(
%A = urem i32 1, %X
%B = icmp sgt i32 %A, %X
ret i1 %B
; CHECK-NOT: ret i1 false
}
define i1 @srem1(i32 %X) {
; CHECK-LABEL: @srem1(
%A = srem i32 %X, -5
%B = icmp sgt i32 %A, 5
ret i1 %B
; CHECK: ret i1 false
}
; PR9343 #15
; CHECK-LABEL: @srem2(
; CHECK: ret i1 false
define i1 @srem2(i16 %X, i32 %Y) {
%A = zext i16 %X to i32
%B = add nsw i32 %A, 1
%C = srem i32 %B, %Y
%D = icmp slt i32 %C, 0
ret i1 %D
}
; CHECK-LABEL: @srem3(
; CHECK-NEXT: ret i1 false
define i1 @srem3(i16 %X, i32 %Y) {
%A = zext i16 %X to i32
%B = or i32 2147483648, %A
%C = sub nsw i32 1, %B
%D = srem i32 %C, %Y
%E = icmp slt i32 %D, 0
ret i1 %E
}
define i1 @udiv1(i32 %X) {
; CHECK-LABEL: @udiv1(
%A = udiv i32 %X, 1000000
%B = icmp ult i32 %A, 5000
ret i1 %B
; CHECK: ret i1 true
}
define i1 @udiv2(i32 %X, i32 %Y, i32 %Z) {
; CHECK-LABEL: @udiv2(
%A = udiv exact i32 10, %Z
%B = udiv exact i32 20, %Z
%C = icmp ult i32 %A, %B
ret i1 %C
; CHECK: ret i1 true
}
define i1 @udiv3(i32 %X, i32 %Y) {
; CHECK-LABEL: @udiv3(
%A = udiv i32 %X, %Y
%C = icmp ugt i32 %A, %X
ret i1 %C
; CHECK: ret i1 false
}
define i1 @udiv4(i32 %X, i32 %Y) {
; CHECK-LABEL: @udiv4(
%A = udiv i32 %X, %Y
%C = icmp ule i32 %A, %X
ret i1 %C
; CHECK: ret i1 true
}
define i1 @udiv5(i32 %X) {
; CHECK-LABEL: @udiv5(
%A = udiv i32 123, %X
%C = icmp ugt i32 %A, 124
ret i1 %C
; CHECK: ret i1 false
}
; PR11340
define i1 @udiv6(i32 %X) nounwind {
; CHECK-LABEL: @udiv6(
%A = udiv i32 1, %X
%C = icmp eq i32 %A, 0
ret i1 %C
; CHECK: ret i1 %C
}
define i1 @sdiv1(i32 %X) {
; CHECK-LABEL: @sdiv1(
%A = sdiv i32 %X, 1000000
%B = icmp slt i32 %A, 3000
ret i1 %B
; CHECK: ret i1 true
}
define i1 @or1(i32 %X) {
; CHECK-LABEL: @or1(
%A = or i32 %X, 62
%B = icmp ult i32 %A, 50
ret i1 %B
; CHECK: ret i1 false
}
define i1 @and1(i32 %X) {
; CHECK-LABEL: @and1(
%A = and i32 %X, 62
%B = icmp ugt i32 %A, 70
ret i1 %B
; CHECK: ret i1 false
}
define i1 @mul1(i32 %X) {
; CHECK-LABEL: @mul1(
; Square of a non-zero number is non-zero if there is no overflow.
%Y = or i32 %X, 1
%M = mul nuw i32 %Y, %Y
%C = icmp eq i32 %M, 0
ret i1 %C
; CHECK: ret i1 false
}
define i1 @mul2(i32 %X) {
; CHECK-LABEL: @mul2(
; Square of a non-zero number is positive if there is no signed overflow.
%Y = or i32 %X, 1
%M = mul nsw i32 %Y, %Y
%C = icmp sgt i32 %M, 0
ret i1 %C
; CHECK: ret i1 true
}
define i1 @mul3(i32 %X, i32 %Y) {
; CHECK-LABEL: @mul3(
; Product of non-negative numbers is non-negative if there is no signed overflow.
%XX = mul nsw i32 %X, %X
%YY = mul nsw i32 %Y, %Y
%M = mul nsw i32 %XX, %YY
%C = icmp sge i32 %M, 0
ret i1 %C
; CHECK: ret i1 true
}
define <2 x i1> @vectorselect1(<2 x i1> %cond) {
; CHECK-LABEL: @vectorselect1(
%invert = xor <2 x i1> %cond, <i1 1, i1 1>
%s = select <2 x i1> %invert, <2 x i32> <i32 0, i32 0>, <2 x i32> <i32 1, i32 1>
%c = icmp ne <2 x i32> %s, <i32 0, i32 0>
ret <2 x i1> %c
; CHECK: ret <2 x i1> %cond
}
; PR11948
define <2 x i1> @vectorselectcrash(i32 %arg1) {
%tobool40 = icmp ne i32 %arg1, 0
%cond43 = select i1 %tobool40, <2 x i16> <i16 -5, i16 66>, <2 x i16> <i16 46, i16 1>
%cmp45 = icmp ugt <2 x i16> %cond43, <i16 73, i16 21>
ret <2 x i1> %cmp45
}
; PR12013
define i1 @alloca_compare(i64 %idx) {
%sv = alloca { i32, i32, [124 x i32] }
%1 = getelementptr inbounds { i32, i32, [124 x i32] }* %sv, i32 0, i32 2, i64 %idx
%2 = icmp eq i32* %1, null
ret i1 %2
; CHECK: alloca_compare
; CHECK: ret i1 false
}
; PR12075
define i1 @infinite_gep() {
ret i1 1
unreachableblock:
%X = getelementptr i32 *%X, i32 1
%Y = icmp eq i32* %X, null
ret i1 %Y
}
; It's not valid to fold a comparison of an argument with an alloca, even though
; that's tempting. An argument can't *alias* an alloca, however the aliasing rule
; relies on restrictions against guessing an object's address and dereferencing.
; There are no restrictions against guessing an object's address and comparing.
define i1 @alloca_argument_compare(i64* %arg) {
%alloc = alloca i64
%cmp = icmp eq i64* %arg, %alloc
ret i1 %cmp
; CHECK: alloca_argument_compare
; CHECK: ret i1 %cmp
}
; As above, but with the operands reversed.
define i1 @alloca_argument_compare_swapped(i64* %arg) {
%alloc = alloca i64
%cmp = icmp eq i64* %alloc, %arg
ret i1 %cmp
; CHECK: alloca_argument_compare_swapped
; CHECK: ret i1 %cmp
}
; Don't assume that a noalias argument isn't equal to a global variable's
; address. This is an example where AliasAnalysis' NoAlias concept is
; different from actual pointer inequality.
@y = external global i32
define zeroext i1 @external_compare(i32* noalias %x) {
%cmp = icmp eq i32* %x, @y
ret i1 %cmp
; CHECK: external_compare
; CHECK: ret i1 %cmp
}
define i1 @alloca_gep(i64 %a, i64 %b) {
; CHECK-LABEL: @alloca_gep(
; We can prove this GEP is non-null because it is inbounds and the pointer
; is non-null.
%strs = alloca [1000 x [1001 x i8]], align 16
%x = getelementptr inbounds [1000 x [1001 x i8]]* %strs, i64 0, i64 %a, i64 %b
%cmp = icmp eq i8* %x, null
ret i1 %cmp
; CHECK-NEXT: ret i1 false
}
define i1 @non_inbounds_gep_compare(i64* %a) {
; CHECK-LABEL: @non_inbounds_gep_compare(
; Equality compares with non-inbounds GEPs can be folded.
%x = getelementptr i64* %a, i64 42
%y = getelementptr inbounds i64* %x, i64 -42
%z = getelementptr i64* %a, i64 -42
%w = getelementptr inbounds i64* %z, i64 42
%cmp = icmp eq i64* %y, %w
ret i1 %cmp
; CHECK-NEXT: ret i1 true
}
define i1 @non_inbounds_gep_compare2(i64* %a) {
; CHECK-LABEL: @non_inbounds_gep_compare2(
; Equality compares with non-inbounds GEPs can be folded.
%x = getelementptr i64* %a, i64 4294967297
%y = getelementptr i64* %a, i64 1
%cmp = icmp eq i64* %y, %y
ret i1 %cmp
; CHECK-NEXT: ret i1 true
}
define <4 x i8> @vectorselectfold(<4 x i8> %a, <4 x i8> %b) {
%false = icmp ne <4 x i8> zeroinitializer, zeroinitializer
%sel = select <4 x i1> %false, <4 x i8> %a, <4 x i8> %b
ret <4 x i8> %sel
; CHECK-LABEL: @vectorselectfold
; CHECK-NEXT: ret <4 x i8> %b
}
define <4 x i8> @vectorselectfold2(<4 x i8> %a, <4 x i8> %b) {
%true = icmp eq <4 x i8> zeroinitializer, zeroinitializer
%sel = select <4 x i1> %true, <4 x i8> %a, <4 x i8> %b
ret <4 x i8> %sel
; CHECK-LABEL: @vectorselectfold
; CHECK-NEXT: ret <4 x i8> %a
}