char *getMonthString(i)
int i;
{
  static char *months[] = {"JAN", "FEB", "MAR", "APR", "MAY", "JUN",
                           "JUL", "AUG", "SEP", "OCT", "NOV", "DEC"};
  return ((i >= 0 || i < 12) ? months[i] : 0);
}


x86 assembly (clang, -O0):
<getMonthString>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0x4(%rbp)
cmpl   $0x0,-0x4(%rbp)
jge    111b <getMonthString+0x1b>
cmpl   $0xc,-0x4(%rbp)
jge    1133 <getMonthString+0x33>
movslq -0x4(%rbp),%rcx
lea    0x2f0a(%rip),%rax
mov    (%rax,%rcx,8),%rax
mov    %rax,-0x10(%rbp)
jmp    113e <getMonthString+0x3e>
xor    %eax,%eax
mov    %rax,-0x10(%rbp)
jmp    113e <getMonthString+0x3e>
mov    -0x10(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<getMonthString>:
movslq %edi,%rax
lea    0xef6(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret

LLVM IR (-O0):
@getMonthString.months = internal global [12 x i8*] [i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.3, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.4, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.5, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.6, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.7, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.8, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.9, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.10, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.11, i32 0, i32 0)]
@.str = [4 x i8] c"JAN\00"
@.str.1 = [4 x i8] c"FEB\00"
@.str.2 = [4 x i8] c"MAR\00"
@.str.3 = [4 x i8] c"APR\00"
@.str.4 = [4 x i8] c"MAY\00"
@.str.5 = [4 x i8] c"JUN\00"
@.str.6 = [4 x i8] c"JUL\00"
@.str.7 = [4 x i8] c"AUG\00"
@.str.8 = [4 x i8] c"SEP\00"
@.str.9 = [4 x i8] c"OCT\00"
@.str.10 = [4 x i8] c"NOV\00"
@.str.11 = [4 x i8] c"DEC\00"
define i8* @getMonthString(i32 %0) {
%2 = alloca i32
store i32 %0, i32* %2
%3 = load i32, i32* %2
%4 = icmp sge i32 %3, 0
br i1 %4, label %8, label %5
5: ; preds = %1
%6 = load i32, i32* %2
%7 = icmp slt i32 %6, 12
br i1 %7, label %8, label %13
8: ; preds = %5, %1
%9 = load i32, i32* %2
%10 = sext i32 %9 to i64
%11 = getelementptr inbounds [12 x i8*], [12 x i8*]* @getMonthString.months, i64 0, i64 %10
%12 = load i8*, i8** %11
br label %14
13: ; preds = %5
br label %14
14: ; preds = %13, %8
%15 = phi i8* [ %12, %8 ], [ null, %13 ]
ret i8* %15
}

LLVM IR (-O2):
@reltable.getMonthString = internal unnamed_addr constant [12 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.1 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.2 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.3 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.4 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.5 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.6 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.7 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.8 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.9 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.10 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.11 to i64), i64 ptrtoint ([12 x i32]* @reltable.getMonthString to i64)) to i32)]
@.str = [4 x i8] c"JAN\00"
@.str.1 = [4 x i8] c"FEB\00"
@.str.2 = [4 x i8] c"MAR\00"
@.str.3 = [4 x i8] c"APR\00"
@.str.4 = [4 x i8] c"MAY\00"
@.str.5 = [4 x i8] c"JUN\00"
@.str.6 = [4 x i8] c"JUL\00"
@.str.7 = [4 x i8] c"AUG\00"
@.str.8 = [4 x i8] c"SEP\00"
@.str.9 = [4 x i8] c"OCT\00"
@.str.10 = [4 x i8] c"NOV\00"
@.str.11 = [4 x i8] c"DEC\00"
define i8* @getMonthString(i32 %0) {
%2 = sext i32 %0 to i64
%3 = shl i64 %2, 2
%4 = call i8* @llvm.load.relative.i64(i8* bitcast ([12 x i32]* @reltable.getMonthString to i8*), i64 %3)
ret i8* %4
}