[LLVMdev] !dbg metadata not generated for if.else->if.end branch

[Bendersky, Eli]

Hello,

For this C code:

int func(int foo, char bar) {
    int result = foo + bar;

    if (foo > bar)
        result += 100 - foo;
    else
        result += 221 - bar;

    return result;
}

Compiled with -O0 -g, the following IR represents the relevant parts of the if/else statement:

  %0 = load i32* %foo.addr, align 4, !dbg !49
  %1 = load i8* %bar.addr, align 1, !dbg !49
  %conv = sext i8 %1 to i32, !dbg !49
  %add = add nsw i32 %0, %conv, !dbg !49
  store i32 %add, i32* %result, align 4, !dbg !49
  %2 = load i32* %foo.addr, align 4, !dbg !50
  %3 = load i8* %bar.addr, align 1, !dbg !50
  %conv1 = sext i8 %3 to i32, !dbg !50
  %cmp = icmp sgt i32 %2, %conv1, !dbg !50
  br i1 %cmp, label %if.then, label %if.else, !dbg !50

if.then:                                          ; preds = %entry
  %4 = load i32* %foo.addr, align 4, !dbg !51
  %sub = sub nsw i32 100, %4, !dbg !51
  %5 = load i32* %result, align 4, !dbg !51
  %add3 = add nsw i32 %5, %sub, !dbg !51
  store i32 %add3, i32* %result, align 4, !dbg !51
  br label %if.end, !dbg !51

if.else:                                          ; preds = %entry
  %6 = load i8* %bar.addr, align 1, !dbg !52
  %conv4 = sext i8 %6 to i32, !dbg !52
  %sub5 = sub nsw i32 221, %conv4, !dbg !52
  %7 = load i32* %result, align 4, !dbg !52
  %add6 = add nsw i32 %7, %sub5, !dbg !52
  store i32 %add6, i32* %result, align 4, !dbg !52
  br label %if.end

if.end:                                           ; preds = %if.else, %if.then
  %8 = load i32* %result, align 4, !dbg !53

----

Note that for the branch from if.else to if.end (br label %if.end), no !dbg metadata is generated.
Is there a good reason for this, or should I open a bug? [I guess this would be for Clang then?]

Eli




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