[Bug tree-optimization/62631] gcc.dg/tree-ssa/ivopts-lt-2.c FAILs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62631 --- Comment #9 from ro at CeBiTec dot Uni-Bielefeld.DE ro at CeBiTec dot Uni-Bielefeld.DE --- --- Comment #8 from Eric Botcazou ebotcazou at gcc dot gnu.org --- I think that's easiest for Eric to say. Not really, I guess you want to debug the function and replay the computation since the cost is synthetized and doesn't come directly from the back-end. I've found what's going on: * In expmed.c (init_expmed_one_mode), l.194 set_shiftadd_cost (speed, mode, m, set_src_cost (all-shift_add, speed)); with all-shift_add something like (plus:QI (mult:QI (reg:QI 109 [0]) (const_int 8 [0x8])) (reg:QI 109 [0])) * For the mult part, rtx_code calls sparc_rtx_cost, which has case MULT: if (float_mode_p) *total = sparc_costs-float_mul; else if (! TARGET_HARD_MUL) *total = COSTS_N_INSNS (25); On SPARCv9/-m64, TARGET_HARD_MUL is false, so we get the 25*4 = 100 part, unlike v8, which explains why the test only fails for 64-bit. Rainer
[Bug tree-optimization/62631] gcc.dg/tree-ssa/ivopts-lt-2.c FAILs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62631 --- Comment #7 from ro at CeBiTec dot Uni-Bielefeld.DE ro at CeBiTec dot Uni-Bielefeld.DE --- --- Comment #6 from amker at gcc dot gnu.org --- (In reply to Rainer Orth from comment #0) The new gcc.dg/tree-ssa/ivopts-lt-2.c test FAILs on 64-bit SPARC (only; 32-bit is ok): FAIL: gcc.dg/tree-ssa/ivopts-lt-2.c scan-tree-dump-times ivopts PHI 1 FAIL: gcc.dg/tree-ssa/ivopts-lt-2.c scan-tree-dump-times ivopts p_[0-9]* 1 I'm attaching the ivopts dump. [...] According to https://gcc.gnu.org/ml/gcc-patches/2014-09/msg00345.html, could you have a look whether the huge cost returned on sparc64 is as expected? I think that's easiest for Eric to say. Rainer
[Bug tree-optimization/62631] gcc.dg/tree-ssa/ivopts-lt-2.c FAILs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62631 Eric Botcazou ebotcazou at gcc dot gnu.org changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2014-09-11 Ever confirmed|0 |1 --- Comment #8 from Eric Botcazou ebotcazou at gcc dot gnu.org --- I think that's easiest for Eric to say. Not really, I guess you want to debug the function and replay the computation since the cost is synthetized and doesn't come directly from the back-end.
[Bug tree-optimization/62631] gcc.dg/tree-ssa/ivopts-lt-2.c FAILs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62631 amker at gcc dot gnu.org changed: What|Removed |Added CC||amker at gcc dot gnu.org --- Comment #6 from amker at gcc dot gnu.org --- (In reply to Rainer Orth from comment #0) The new gcc.dg/tree-ssa/ivopts-lt-2.c test FAILs on 64-bit SPARC (only; 32-bit is ok): FAIL: gcc.dg/tree-ssa/ivopts-lt-2.c scan-tree-dump-times ivopts PHI 1 FAIL: gcc.dg/tree-ssa/ivopts-lt-2.c scan-tree-dump-times ivopts p_[0-9]* 1 I'm attaching the ivopts dump. Rainer Hi, According to https://gcc.gnu.org/ml/gcc-patches/2014-09/msg00345.html, could you have a look whether the huge cost returned on sparc64 is as expected? Thanks very much.
[Bug tree-optimization/62631] gcc.dg/tree-ssa/ivopts-lt-2.c FAILs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62631 John David Anglin danglin at gcc dot gnu.org changed: What|Removed |Added CC||danglin at gcc dot gnu.org --- Comment #5 from John David Anglin danglin at gcc dot gnu.org --- Also seen on 32-bit hppa*-*-*. 64-bit is OK.
[Bug tree-optimization/62631] gcc.dg/tree-ssa/ivopts-lt-2.c FAILs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62631 --- Comment #4 from bin.cheng amker.cheng at gmail dot com --- Hi Rainer, This is caused by abnormal huge cost of function call `shiftadd_cost (true, DImode, 2)'. It returns 100+ cost, resulting in huge cost when representing use 1 with cand 4: use 1 compare in statement if (i_12 = 99) at position type unsigned int base i_4(D) + 1 step 1 is a biv related candidates i_4(D) is invariant (2), eliminable p_8 is invariant (1), eliminable candidate 4 (important) original biv type int * base p_8 step 4 base object (void *) p_8 Use 1: candcostcompl.depends on 040 inv_expr:0 140 4230 inv_expr:1 --huge cost. 500 600 841 I worked out a patch fixing this from ivopt. Because I am not firmiliar with sparc ISA, could you please help me confirm that below fixed assembly is better than the original version? The orignal assembly: f1: sllx%o1, 2, %g1 add%o0, %g1, %o0 .LL2: st%g0, [%o0] add%o1, 1, %g1 add%o0, 4, %o0 cmp%g1, 99 bleu,pt%icc, .LL2 srl%g1, 0, %o1 jmp%o7+8 nop .sizef1, .-f1 The fixed version assembly: f1: .register%g2, #scratch sllx%o1, 2, %g1 mov99, %g2 add%o0, %g1, %o0 sub%g2, %o1, %o1 srl%o1, 0, %g1 add%g1, 1, %g1 sllx%g1, 2, %g1 add%o0, %g1, %g1 st%g0, [%o0] .LL5: add%o0, 4, %o0 cmp%o0, %g1 blu,a,pt %xcc, .LL5 st%g0, [%o0] jmp%o7+8 nop .sizef1, .-f1 Though it has larger loop setup code, the loop itself is simplified. If yes, I will send out the patch for review. Thanks, bin
[Bug tree-optimization/62631] gcc.dg/tree-ssa/ivopts-lt-2.c FAILs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62631 Rainer Orth ro at gcc dot gnu.org changed: What|Removed |Added Target Milestone|--- |5.0
[Bug tree-optimization/62631] gcc.dg/tree-ssa/ivopts-lt-2.c FAILs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62631 --- Comment #1 from Rainer Orth ro at gcc dot gnu.org --- Created attachment 33427 -- https://gcc.gnu.org/bugzilla/attachment.cgi?id=33427action=edit ivopts dump
[Bug tree-optimization/62631] gcc.dg/tree-ssa/ivopts-lt-2.c FAILs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62631 --- Comment #2 from Rainer Orth ro at gcc dot gnu.org --- Created attachment 33428 -- https://gcc.gnu.org/bugzilla/attachment.cgi?id=33428action=edit slp dump
[Bug tree-optimization/62631] gcc.dg/tree-ssa/ivopts-lt-2.c FAILs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62631 --- Comment #3 from Rainer Orth ro at gcc dot gnu.org --- Created attachment 33429 -- https://gcc.gnu.org/bugzilla/attachment.cgi?id=33429action=edit bb-slp-26.c.120t.slp1 dump
