"Deepti Sharma" <deepti.gccretarget@xxxxxxxxx> writes: > After battling with this error for several hours, I was able to resolve this > error simply by putting my nop instruction pattern as the first pattern. > Initially, I had movqi as my first instruction pattern. Is this some > restriction or a bug in gcc? > ... > Could you please elaborate on this behaviour? I could not find any such > restriction in the gcc documentation. I don't know what the problem is because I don't have any detailed information about the change you made to GCC. There is nothing special about the first insn in the MD file. The only way in which ordering is important is that RTL patterns are matched against insns in order. It's normally a bug if two insns match an RTL pattern, but there are unusual cases where that is desirable, and then order matters. Ian