char *mem_str(int off) {
  char *pstr;
  switch (off) {
  case 0x00:
    pstr = "Correctable ECC";
    break;
  case 0x01:
    pstr = "Uncorrectable ECC";
    break;
  case 0x02:
    pstr = "Parity";
    break;
  case 0x03:
    pstr = "Memory Scrub Failed";
    break;
  case 0x04:
    pstr = "Memory Device Disabled";
    break;
  case 0x05:
    pstr = "ECC limit reached";
    break;
  case 0x07:
    pstr = "SMI Link Lane Fail Over";
    break;
  default:
    pstr = "Other Memory Error";
    break;
  }
  return (pstr);
}


x86 assembly (clang, -O0):
<mem_str>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0x4(%rbp)
mov    -0x4(%rbp),%eax
mov    %rax,-0x18(%rbp)
sub    $0x7,%rax
ja     119c <mem_str+0x9c>
mov    -0x18(%rbp),%rax
lea    0xedd(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xeed(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11a7 <mem_str+0xa7>
lea    0xeed(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11a7 <mem_str+0xa7>
lea    0xeef(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11a7 <mem_str+0xa7>
lea    0xee6(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11a7 <mem_str+0xa7>
lea    0xeea(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11a7 <mem_str+0xa7>
lea    0xef1(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11a7 <mem_str+0xa7>
lea    0xef3(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11a7 <mem_str+0xa7>
lea    0xefb(%rip),%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<mem_str>:
cmp    $0x7,%edi
ja     1117 <mem_str+0x17>
movslq %edi,%rax
lea    0xf85(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xf60(%rip),%rax
ret

LLVM IR (-O0):
@.str = [16 x i8] c"Correctable ECC\00"
@.str.1 = [18 x i8] c"Uncorrectable ECC\00"
@.str.2 = [7 x i8] c"Parity\00"
@.str.3 = [20 x i8] c"Memory Scrub Failed\00"
@.str.4 = [23 x i8] c"Memory Device Disabled\00"
@.str.5 = [18 x i8] c"ECC limit reached\00"
@.str.6 = [24 x i8] c"SMI Link Lane Fail Over\00"
@.str.7 = [19 x i8] c"Other Memory Error\00"
define i8* @mem_str(i32 %0) {
%2 = alloca i32
%3 = alloca i8*
store i32 %0, i32* %2
%4 = load i32, i32* %2
switch i32 %4, label %12 [
i32 0, label %5
i32 1, label %6
i32 2, label %7
i32 3, label %8
i32 4, label %9
i32 5, label %10
i32 7, label %11
]
5: ; preds = %1
store i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str, i64 0, i64 0), i8** %3
br label %13
6: ; preds = %1
store i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str.1, i64 0, i64 0), i8** %3
br label %13
7: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.2, i64 0, i64 0), i8** %3
br label %13
8: ; preds = %1
store i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.3, i64 0, i64 0), i8** %3
br label %13
9: ; preds = %1
store i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str.4, i64 0, i64 0), i8** %3
br label %13
10: ; preds = %1
store i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str.5, i64 0, i64 0), i8** %3
br label %13
11: ; preds = %1
store i8* getelementptr inbounds ([24 x i8], [24 x i8]* @.str.6, i64 0, i64 0), i8** %3
br label %13
12: ; preds = %1
store i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.7, i64 0, i64 0), i8** %3
br label %13
13: ; preds = %12, %11, %10, %9, %8, %7, %6, %5
%14 = load i8*, i8** %3
ret i8* %14
}

LLVM IR (-O2):
@.str = [16 x i8] c"Correctable ECC\00"
@.str.1 = [18 x i8] c"Uncorrectable ECC\00"
@.str.2 = [7 x i8] c"Parity\00"
@.str.3 = [20 x i8] c"Memory Scrub Failed\00"
@.str.4 = [23 x i8] c"Memory Device Disabled\00"
@.str.5 = [18 x i8] c"ECC limit reached\00"
@.str.6 = [24 x i8] c"SMI Link Lane Fail Over\00"
@.str.7 = [19 x i8] c"Other Memory Error\00"
@reltable.mem_str = [8 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([16 x i8]* @.str to i64), i64 ptrtoint ([8 x i32]* @reltable.mem_str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([18 x i8]* @.str.1 to i64), i64 ptrtoint ([8 x i32]* @reltable.mem_str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.2 to i64), i64 ptrtoint ([8 x i32]* @reltable.mem_str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([20 x i8]* @.str.3 to i64), i64 ptrtoint ([8 x i32]* @reltable.mem_str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([23 x i8]* @.str.4 to i64), i64 ptrtoint ([8 x i32]* @reltable.mem_str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([18 x i8]* @.str.5 to i64), i64 ptrtoint ([8 x i32]* @reltable.mem_str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([19 x i8]* @.str.7 to i64), i64 ptrtoint ([8 x i32]* @reltable.mem_str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([24 x i8]* @.str.6 to i64), i64 ptrtoint ([8 x i32]* @reltable.mem_str to i64)) to i32)]
define i8* @mem_str(i32 %0) {
%2 = icmp ult i32 %0, 8
br i1 %2, label %3, label %7
3: ; preds = %1
%4 = sext i32 %0 to i64
%5 = shl i64 %4, 2
%6 = call i8* @llvm.load.relative.i64(i8* bitcast ([8 x i32]* @reltable.mem_str to i8*), i64 %5)
br label %7
7: ; preds = %1, %3
%8 = phi i8* [ %6, %3 ], [ getelementptr inbounds ([19 x i8], [19 x i8]* @.str.7, i64 0, i64 0), %1 ]
ret i8* %8
}