On Thu, May 08, 2014 at 09:48:35AM -0400, David Edelsohn wrote: > The history is 32 bit HWI.
Right. > The ChangeLog does not mention the changes to rs6000.md nor rs6000-protos.h. Oops, added. * config/rs6000/rs6000.md (movsi_internal1_single+1): Update call to rs6000_emit_set_const in splitter. (movdi_internal64+2, +3): Likewise. * config/rs6000/rs6000-protos.h (rs6000_emit_set_const): Update prototype. > Please do not remove all of the comments from the two functions. The > comments should provide some documentation about the different > purposes of the two functions other than setting DEST to a CONST. I believe my updated comment covers the complete purpose of the function nowadays. The comments I removed are out-dated, and should have been removed a long time ago.. rs6000_emit_set_const does not even look at N, it always returns a non-zero result, and the return is only tested for non-zero. I removed MODE too, because that is always the same as GET_MODE (dest). > Why did you remove the test for NULL dest? > > - if (dest == NULL) > - dest = gen_reg_rtx (mode); > > That could occur, at least it used to occur. I'm sure we can't get a NULL dest nowadays. All (three) uses of rs6000_emit_set_const occur in splitters. They all must have passed a gpc_reg_operand constraint on operands[0] before calling rs6000_emit_set_const, so if NULL were possible we'd segfault in gpc_reg_operand. > I think that the way you rearranged the invocations of copy_rtx() in > rs6000_emit_set_long_const() is okay, but it would be good for someone > else to double check. Yeah, that function is a bit messy. I took the approach of always use a bare "dest" once in the last instruction emitted, with every other use getting hit with copy_rtx. The previous approach was similar, but used the bare "dest" on the first instruction emitted. Obviously you don't need copy_rtx anywhere with the new code when can_create_pseudo_p is true, but I felt it wasn't worth optimising that for the added source complication. -- Alan Modra Australia Development Lab, IBM