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[Bug tree-optimization/56049] [4.8 Regression] Simplification to constants not done
- From: "hubicka at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 11 Feb 2013 22:55:44 +0000
- Subject: [Bug tree-optimization/56049] [4.8 Regression] Simplification to constants not done
- Auto-submitted: auto-generated
- References: <bug-56049-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56049
--- Comment #5 from Jan Hubicka <hubicka at gcc dot gnu.org> 2013-02-11 22:55:44 UTC ---
Well, I think we should try to toamn fantasy of our optimizers here. What
unroller sees at -O3 -fno-tree-vectorize is quite ugly:
<bb 2>:
a = {};
<bb 3>:
# i_1 = PHI <1(2), i_7(7)>
# prephitmp_99 = PHI <0(2), pretmp_98(7)>
# prephitmp_102 = PHI <0(2), pretmp_101(7)>
# prephitmp_105 = PHI <0(2), pretmp_104(7)>
# prephitmp_108 = PHI <0(2), pretmp_107(7)>
# prephitmp_111 = PHI <0(2), pretmp_110(7)>
# prephitmp_114 = PHI <0(2), pretmp_113(7)>
# prephitmp_117 = PHI <0(2), pretmp_116(7)>
# prephitmp_120 = PHI <0(2), pretmp_119(7)>
# ivtmp_57 = PHI <10000000(2), ivtmp_64(7)>
<bb 4>:
# S.0_90 = PHI <S.0_36(5), 1(3)>
# prephitmp_126 = PHI <pretmp_125(5), prephitmp_99(3)>
# prephitmp_129 = PHI <pretmp_128(5), prephitmp_102(3)>
# prephitmp_132 = PHI <pretmp_131(5), prephitmp_105(3)>
# prephitmp_135 = PHI <pretmp_134(5), prephitmp_108(3)>
# prephitmp_138 = PHI <pretmp_137(5), prephitmp_111(3)>
# prephitmp_141 = PHI <pretmp_140(5), prephitmp_114(3)>
# prephitmp_144 = PHI <pretmp_143(5), prephitmp_117(3)>
# prephitmp_147 = PHI <pretmp_146(5), prephitmp_120(3)>
# ivtmp_43 = PHI <ivtmp_50(5), 8(3)>
_29 = S.0_90 * 8;
_42 = _29 + -8;
_44 = prephitmp_126 + 1;
b[_42] = _44;
_49 = _29 + -7;
_51 = prephitmp_129 + 1;
b[_49] = _51;
_56 = _29 + -6;
_58 = prephitmp_132 + 1;
b[_56] = _58;
_63 = _29 + -5;
_65 = prephitmp_135 + 1;
b[_63] = _65;
_70 = _29 + -4;
b[_63] = _65;
_70 = _29 + -4;
_72 = prephitmp_138 + 1;
b[_70] = _72;
_77 = _29 + -3;
_79 = prephitmp_141 + 1;
b[_77] = _79;
_84 = _29 + -2;
_86 = prephitmp_144 + 1;
b[_84] = _86;
_91 = _29 + -1;
_93 = prephitmp_147 + 1;
b[_91] = _93;
S.0_36 = S.0_90 + 1;
ivtmp_50 = ivtmp_43 - 1;
if (ivtmp_50 == 0)
goto <bb 6>;
else
goto <bb 5>;
<bb 5>:
pretmp_122 = S.0_36 * 8;
pretmp_124 = pretmp_122 + -8;
pretmp_125 = a[pretmp_124];
pretmp_127 = pretmp_122 + -7;
pretmp_128 = a[pretmp_127];
pretmp_130 = pretmp_122 + -6;
pretmp_131 = a[pretmp_130];
pretmp_133 = pretmp_122 + -5;
pretmp_134 = a[pretmp_133];
pretmp_136 = pretmp_122 + -4;
pretmp_137 = a[pretmp_136];
pretmp_139 = pretmp_122 + -3;
pretmp_140 = a[pretmp_139];
pretmp_142 = pretmp_122 + -2;
pretmp_143 = a[pretmp_142];
pretmp_145 = pretmp_122 + -1;
pretmp_146 = a[pretmp_145];
goto <bb 4>;
With vectorization we actually unroll the inner loop but the outer one gets so
ugly that we don't do much about it...
So what about keeping it as enhancement request? I will try to poke about it,
but htere is but about PR overactivity of this type already, right?