On 27/08/14 20:01, Uros Bizjak wrote: > Hello! > >> 2014-08-07 Kugan Vivekanandarajah <kug...@linaro.org> >> >> * calls.c (precompute_arguments): Check >> promoted_for_signed_and_unsigned_p and set the promoted mode. >> (promoted_for_signed_and_unsigned_p): New function. >> (expand_expr_real_1): Check promoted_for_signed_and_unsigned_p >> and set the promoted mode. >> * expr.h (promoted_for_signed_and_unsigned_p): New function definition. >> * cfgexpand.c (expand_gimple_stmt_1): Call emit_move_insn if >> SUBREG is promoted with SRP_SIGNED_AND_UNSIGNED. > > This patch regresses: > > Running target unix > FAIL: libgomp.fortran/simd7.f90 -O2 execution test > FAIL: libgomp.fortran/simd7.f90 -Os execution test >
[snip] > When compiling this code, we have: > > lhs = _63 > target = (subreg/s/v/u:SI (reg:DI 145 [ D.1694 ]) 0) > temp = (subreg:SI (reg:DI 540) 0) > > So, the code assumes that it is possible to copy (reg:DI 540) directly > to (reg:DI 154). However, this is not the case, since we still have > garbage in the top 32bits. > > Reverting the part above fixes the runtime failure, since (insn 599) is now: > > (insn 599 598 0 (set (reg:DI 145 [ D.1694 ]) > (zero_extend:DI (subreg:SI (reg:DI 540) 0))) -1 > (nil)) > > It looks to me that we have also to check the temp with SUBREG_PROMOTED_*. Sorry for the breakage. I am looking into this now and I can reproduce it on qemu-alpha. I have noticed the following VRP data which is used in deciding this erroneous removal. It seems suspicious to me. _343: [2147483652, 2147483715] _344: [8, 134] _345: [8, 134] _343 = ivtmp.179_52 + 2147483645; _344 = _343 * 2; _345 = (integer(kind=4)) _344; Error comes from the third statement. Thanks, Kugan
