On Sun, Oct 04, 2015 at 04:53:23PM -0400, Marios Pomonis wrote: > I'm trying to add some instructions in the beginning of each function > using a gcc plugin in RTL (after "vartrack"). > I am currently doing this by iterating the instructions in the first > basic block and calling `emit_insn_before()' when reaching the first > "real" instruction (one that has INSN, CALL or JUMP as code). > > This works ok if the first "real" instruction is not part of a loop, > because in this case the additional instructions are also executed as well. > I know that this happens because there is at least one CODE_LABEL rtx > before the first "real" instruction, however all my attempts to fix this > (e.g. by adding the additional instructions before the labels and > splitting the basic block) failed. > > Does anyone have a suggestion on how this should be fixed properly? You split the entry edge, and you put the insns in the new basic block. Or, less manually, you use insert_insn_on_edge (on the entry edge) and then commit_edge_insertions. Segher
