On 12/01/2015 12:32 PM, Richard Sandiford wrote:
Jeff Law <l...@redhat.com> writes:@@ -1080,6 +1070,18 @@ add_removable_extension (const_rtx expr, rtx_insn *insn, } }+ /* Fourth, if the extended version occupies more registers than the + original and the source of the extension is the same hard register + as the destination of the extension, then we can not eliminate + the extension without deep analysis, so just punt. + + We allow this when the registers are different because the + code in combine_reaching_defs will handle that case correctly. */ + if ((HARD_REGNO_NREGS (REGNO (dest), mode) + != HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg))) + && REGNO (dest) == REGNO (reg)) + return; + /* Then add the candidate to the list and insert the reaching definitions into the definition map. */ ext_cand e = {expr, code, mode, insn};I might be wrong, but the check looks specific to little-endian. Would it make sense to use reg_overlap_mentioned_p instead of the REGNO check?
Agreed. Testing in progress now... jeff
