Should convert if with a head controlled loop to a tail controlled loop

[rfalke]

Exe: https://github.com/rfalke/decompiler-subjects/blob/master/from_holdec/dmi/cfg/ia32_elf/subject.exe
Reko version: 46f203b

Input

int intermediate_11_loop_with_two_breaks(int arg)
{
	while (arg > 0) {
		puts("head");
		if (time(0) == arg) {
			break;
		}
		puts("tail");
		arg--;
	}
	return 0;
}

Output

// 080487E0: void intermediate_11_loop_with_two_breaks(Stack Eq_19 dwArg04)
void intermediate_11_loop_with_two_breaks(Eq_19 dwArg04)
{
	Eq_19 ebx_22 = dwArg04;
	if (dwArg04 > 0x00)
	{
		do
		{
			puts("head");
			if (time(null) == ebx_22)
				return;
			puts("tail");
			ebx_22 = ebx_22 - 0x01;
		} while (ebx_22 != 0x00);
	}
}

The output is more complex with the if. The decompiler has enough information to convert this to a head controlled while loop.

[uxmal]

Gated do-loops are now handled by Reko, if the condition in the if statement matches the condition in the do-loop. Sadly, Reko is failing to understand that dwArg04 and ebx_22 are the same variable, so this particular case remains broken.

[rfalke]

Output of 0.11.4.0-931ca7d:

void intermediate_11_loop_with_two_breaks(Eq_10 dwArg04)
{
	Eq_10 ebx_22 = dwArg04;
	if (dwArg04 > 0x00)
	{
		do
		{
			puts("head");
			if (time(null) == ebx_22)
				return;
			puts("tail");
			--ebx_22;
		} while (ebx_22 != 0x00);
	}
}

The problem still exists.

I'm not sure if it is the variable aliasing which is the problem or that the fact that the conditions (x > 0x00 vs y != 0x00)) are not the same.