int IS_ALPHABET(char c) {
  return 97 == c || 98 == c || 99 == c || 100 == c || 101 == c || 102 == c ||
         103 == c || 104 == c || 105 == c || 106 == c || 107 == c || 108 == c ||
         109 == c || 110 == c || 111 == c || 112 == c || 113 == c || 114 == c ||
         115 == c || 116 == c || 117 == c || 118 == c || 119 == c || 120 == c ||
         121 == c || 122 == c || 65 == c || 66 == c || 67 == c || 68 == c ||
         69 == c || 70 == c || 71 == c || 72 == c || 73 == c || 74 == c ||
         75 == c || 76 == c || 77 == c || 78 == c || 79 == c || 80 == c ||
         81 == c || 82 == c || 83 == c || 84 == c || 85 == c || 86 == c ||
         87 == c || 88 == c || 89 == c || 90 == c;
}


x86 assembly (clang, -O0):
<IS_ALPHABET>:
push   %rbp
mov    %rsp,%rbp
mov    %dil,%al
mov    %al,-0x1(%rbp)
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x61,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x62,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x63,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x64,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x65,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x66,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x67,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x68,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x69,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x6a,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x6b,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x6c,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x6d,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x6e,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x6f,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x70,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x71,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x72,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x73,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x74,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x75,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x76,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x77,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x78,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x79,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x7a,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x41,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x42,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x43,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x44,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x45,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x46,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x47,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x48,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x49,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x4a,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x4b,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x4c,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x4d,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x4e,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x4f,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x50,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x51,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x52,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x53,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x54,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x55,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x56,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x57,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x58,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%edx
mov    $0x1,%al
mov    $0x59,%ecx
cmp    %edx,%ecx
mov    %al,-0x2(%rbp)
je     157d <IS_ALPHABET+0x47d>
movsbl -0x1(%rbp),%ecx
mov    $0x5a,%eax
cmp    %ecx,%eax
sete   %al
mov    %al,-0x2(%rbp)
mov    -0x2(%rbp),%al
and    $0x1,%al
movzbl %al,%eax
pop    %rbp
ret

x86 assembly (clang, -O2):
<IS_ALPHABET>:
and    $0xdf,%dil
add    $0xbf,%dil
xor    %eax,%eax
cmp    $0x1a,%dil
setb   %al
ret

LLVM IR (-O0):
define i32 @IS_ALPHABET(i8 signext %0) {
%2 = alloca i8
store i8 %0, i8* %2
%3 = load i8, i8* %2
%4 = sext i8 %3 to i32
%5 = icmp eq i32 97, %4
br i1 %5, label %210, label %6
6: ; preds = %1
%7 = load i8, i8* %2
%8 = sext i8 %7 to i32
%9 = icmp eq i32 98, %8
br i1 %9, label %210, label %10
10: ; preds = %6
%11 = load i8, i8* %2
%12 = sext i8 %11 to i32
%13 = icmp eq i32 99, %12
br i1 %13, label %210, label %14
14: ; preds = %10
%15 = load i8, i8* %2
%16 = sext i8 %15 to i32
%17 = icmp eq i32 100, %16
br i1 %17, label %210, label %18
18: ; preds = %14
%19 = load i8, i8* %2
%20 = sext i8 %19 to i32
%21 = icmp eq i32 101, %20
br i1 %21, label %210, label %22
22: ; preds = %18
%23 = load i8, i8* %2
%24 = sext i8 %23 to i32
%25 = icmp eq i32 102, %24
br i1 %25, label %210, label %26
26: ; preds = %22
%27 = load i8, i8* %2
%28 = sext i8 %27 to i32
%29 = icmp eq i32 103, %28
br i1 %29, label %210, label %30
30: ; preds = %26
%31 = load i8, i8* %2
%32 = sext i8 %31 to i32
%33 = icmp eq i32 104, %32
br i1 %33, label %210, label %34
34: ; preds = %30
%35 = load i8, i8* %2
%36 = sext i8 %35 to i32
%37 = icmp eq i32 105, %36
br i1 %37, label %210, label %38
38: ; preds = %34
%39 = load i8, i8* %2
%40 = sext i8 %39 to i32
%41 = icmp eq i32 106, %40
br i1 %41, label %210, label %42
42: ; preds = %38
%43 = load i8, i8* %2
%44 = sext i8 %43 to i32
%45 = icmp eq i32 107, %44
br i1 %45, label %210, label %46
46: ; preds = %42
%47 = load i8, i8* %2
%48 = sext i8 %47 to i32
%49 = icmp eq i32 108, %48
br i1 %49, label %210, label %50
50: ; preds = %46
%51 = load i8, i8* %2
%52 = sext i8 %51 to i32
%53 = icmp eq i32 109, %52
br i1 %53, label %210, label %54
54: ; preds = %50
%55 = load i8, i8* %2
%56 = sext i8 %55 to i32
%57 = icmp eq i32 110, %56
br i1 %57, label %210, label %58
58: ; preds = %54
%59 = load i8, i8* %2
%60 = sext i8 %59 to i32
%61 = icmp eq i32 111, %60
br i1 %61, label %210, label %62
62: ; preds = %58
%63 = load i8, i8* %2
%64 = sext i8 %63 to i32
%65 = icmp eq i32 112, %64
br i1 %65, label %210, label %66
66: ; preds = %62
%67 = load i8, i8* %2
%68 = sext i8 %67 to i32
%69 = icmp eq i32 113, %68
br i1 %69, label %210, label %70
70: ; preds = %66
%71 = load i8, i8* %2
%72 = sext i8 %71 to i32
%73 = icmp eq i32 114, %72
br i1 %73, label %210, label %74
74: ; preds = %70
%75 = load i8, i8* %2
%76 = sext i8 %75 to i32
%77 = icmp eq i32 115, %76
br i1 %77, label %210, label %78
78: ; preds = %74
%79 = load i8, i8* %2
%80 = sext i8 %79 to i32
%81 = icmp eq i32 116, %80
br i1 %81, label %210, label %82
82: ; preds = %78
%83 = load i8, i8* %2
%84 = sext i8 %83 to i32
%85 = icmp eq i32 117, %84
br i1 %85, label %210, label %86
86: ; preds = %82
%87 = load i8, i8* %2
%88 = sext i8 %87 to i32
%89 = icmp eq i32 118, %88
br i1 %89, label %210, label %90
90: ; preds = %86
%91 = load i8, i8* %2
%92 = sext i8 %91 to i32
%93 = icmp eq i32 119, %92
br i1 %93, label %210, label %94
94: ; preds = %90
%95 = load i8, i8* %2
%96 = sext i8 %95 to i32
%97 = icmp eq i32 120, %96
br i1 %97, label %210, label %98
98: ; preds = %94
%99 = load i8, i8* %2
%100 = sext i8 %99 to i32
%101 = icmp eq i32 121, %100
br i1 %101, label %210, label %102
102: ; preds = %98
%103 = load i8, i8* %2
%104 = sext i8 %103 to i32
%105 = icmp eq i32 122, %104
br i1 %105, label %210, label %106
106: ; preds = %102
%107 = load i8, i8* %2
%108 = sext i8 %107 to i32
%109 = icmp eq i32 65, %108
br i1 %109, label %210, label %110
110: ; preds = %106
%111 = load i8, i8* %2
%112 = sext i8 %111 to i32
%113 = icmp eq i32 66, %112
br i1 %113, label %210, label %114
114: ; preds = %110
%115 = load i8, i8* %2
%116 = sext i8 %115 to i32
%117 = icmp eq i32 67, %116
br i1 %117, label %210, label %118
118: ; preds = %114
%119 = load i8, i8* %2
%120 = sext i8 %119 to i32
%121 = icmp eq i32 68, %120
br i1 %121, label %210, label %122
122: ; preds = %118
%123 = load i8, i8* %2
%124 = sext i8 %123 to i32
%125 = icmp eq i32 69, %124
br i1 %125, label %210, label %126
126: ; preds = %122
%127 = load i8, i8* %2
%128 = sext i8 %127 to i32
%129 = icmp eq i32 70, %128
br i1 %129, label %210, label %130
130: ; preds = %126
%131 = load i8, i8* %2
%132 = sext i8 %131 to i32
%133 = icmp eq i32 71, %132
br i1 %133, label %210, label %134
134: ; preds = %130
%135 = load i8, i8* %2
%136 = sext i8 %135 to i32
%137 = icmp eq i32 72, %136
br i1 %137, label %210, label %138
138: ; preds = %134
%139 = load i8, i8* %2
%140 = sext i8 %139 to i32
%141 = icmp eq i32 73, %140
br i1 %141, label %210, label %142
142: ; preds = %138
%143 = load i8, i8* %2
%144 = sext i8 %143 to i32
%145 = icmp eq i32 74, %144
br i1 %145, label %210, label %146
146: ; preds = %142
%147 = load i8, i8* %2
%148 = sext i8 %147 to i32
%149 = icmp eq i32 75, %148
br i1 %149, label %210, label %150
150: ; preds = %146
%151 = load i8, i8* %2
%152 = sext i8 %151 to i32
%153 = icmp eq i32 76, %152
br i1 %153, label %210, label %154
154: ; preds = %150
%155 = load i8, i8* %2
%156 = sext i8 %155 to i32
%157 = icmp eq i32 77, %156
br i1 %157, label %210, label %158
158: ; preds = %154
%159 = load i8, i8* %2
%160 = sext i8 %159 to i32
%161 = icmp eq i32 78, %160
br i1 %161, label %210, label %162
162: ; preds = %158
%163 = load i8, i8* %2
%164 = sext i8 %163 to i32
%165 = icmp eq i32 79, %164
br i1 %165, label %210, label %166
166: ; preds = %162
%167 = load i8, i8* %2
%168 = sext i8 %167 to i32
%169 = icmp eq i32 80, %168
br i1 %169, label %210, label %170
170: ; preds = %166
%171 = load i8, i8* %2
%172 = sext i8 %171 to i32
%173 = icmp eq i32 81, %172
br i1 %173, label %210, label %174
174: ; preds = %170
%175 = load i8, i8* %2
%176 = sext i8 %175 to i32
%177 = icmp eq i32 82, %176
br i1 %177, label %210, label %178
178: ; preds = %174
%179 = load i8, i8* %2
%180 = sext i8 %179 to i32
%181 = icmp eq i32 83, %180
br i1 %181, label %210, label %182
182: ; preds = %178
%183 = load i8, i8* %2
%184 = sext i8 %183 to i32
%185 = icmp eq i32 84, %184
br i1 %185, label %210, label %186
186: ; preds = %182
%187 = load i8, i8* %2
%188 = sext i8 %187 to i32
%189 = icmp eq i32 85, %188
br i1 %189, label %210, label %190
190: ; preds = %186
%191 = load i8, i8* %2
%192 = sext i8 %191 to i32
%193 = icmp eq i32 86, %192
br i1 %193, label %210, label %194
194: ; preds = %190
%195 = load i8, i8* %2
%196 = sext i8 %195 to i32
%197 = icmp eq i32 87, %196
br i1 %197, label %210, label %198
198: ; preds = %194
%199 = load i8, i8* %2
%200 = sext i8 %199 to i32
%201 = icmp eq i32 88, %200
br i1 %201, label %210, label %202
202: ; preds = %198
%203 = load i8, i8* %2
%204 = sext i8 %203 to i32
%205 = icmp eq i32 89, %204
br i1 %205, label %210, label %206
206: ; preds = %202
%207 = load i8, i8* %2
%208 = sext i8 %207 to i32
%209 = icmp eq i32 90, %208
br label %210
210: ; preds = %206, %202, %198, %194, %190, %186, %182, %178, %174, %170, %166, %162, %158, %154, %150, %146, %142, %138, %134, %130, %126, %122, %118, %114, %110, %106, %102, %98, %94, %90, %86, %82, %78, %74, %70, %66, %62, %58, %54, %50, %46, %42, %38, %34, %30, %26, %22, %18, %14, %10, %6, %1
%211 = phi i1 [ true, %202 ], [ true, %198 ], [ true, %194 ], [ true, %190 ], [ true, %186 ], [ true, %182 ], [ true, %178 ], [ true, %174 ], [ true, %170 ], [ true, %166 ], [ true, %162 ], [ true, %158 ], [ true, %154 ], [ true, %150 ], [ true, %146 ], [ true, %142 ], [ true, %138 ], [ true, %134 ], [ true, %130 ], [ true, %126 ], [ true, %122 ], [ true, %118 ], [ true, %114 ], [ true, %110 ], [ true, %106 ], [ true, %102 ], [ true, %98 ], [ true, %94 ], [ true, %90 ], [ true, %86 ], [ true, %82 ], [ true, %78 ], [ true, %74 ], [ true, %70 ], [ true, %66 ], [ true, %62 ], [ true, %58 ], [ true, %54 ], [ true, %50 ], [ true, %46 ], [ true, %42 ], [ true, %38 ], [ true, %34 ], [ true, %30 ], [ true, %26 ], [ true, %22 ], [ true, %18 ], [ true, %14 ], [ true, %10 ], [ true, %6 ], [ true, %1 ], [ %209, %206 ]
%212 = zext i1 %211 to i32
ret i32 %212
}

LLVM IR (-O2):
define i32 @IS_ALPHABET(i8 signext %0) {
%2 = and i8 %0, -33
%3 = add i8 %2, -65
%4 = icmp ult i8 %3, 26
%5 = zext i1 %4 to i32
ret i32 %5
}