| 1 | --- a/gcc/tree-ssa-tail-merge.c |
| 2 | +++ b/gcc/tree-ssa-tail-merge.c |
| 3 | @@ -1033,7 +1033,7 @@ set_cluster (basic_block bb1, basic_bloc |
| 4 | gimple_bb (s2) are members of SAME_SUCC. */ |
| 5 | |
| 6 | static bool |
| 7 | -gimple_equal_p (same_succ same_succ, gimple s1, gimple s2) |
| 8 | +gimple_equal_p (same_succ same_succ, gimple s1, gimple s2, bool *gvn_used) |
| 9 | { |
| 10 | unsigned int i; |
| 11 | tree lhs1, lhs2; |
| 12 | @@ -1069,7 +1069,10 @@ gimple_equal_p (same_succ same_succ, gim |
| 13 | if (operand_equal_p (t1, t2, 0)) |
| 14 | continue; |
| 15 | if (gvn_uses_equal (t1, t2)) |
| 16 | - continue; |
| 17 | + { |
| 18 | + *gvn_used = true; |
| 19 | + continue; |
| 20 | + } |
| 21 | equal = false; |
| 22 | break; |
| 23 | } |
| 24 | @@ -1083,12 +1086,16 @@ gimple_equal_p (same_succ same_succ, gim |
| 25 | if (lhs1 == NULL_TREE || lhs2 == NULL_TREE) |
| 26 | return false; |
| 27 | if (TREE_CODE (lhs1) == SSA_NAME && TREE_CODE (lhs2) == SSA_NAME) |
| 28 | - return vn_valueize (lhs1) == vn_valueize (lhs2); |
| 29 | + { |
| 30 | + *gvn_used = true; |
| 31 | + return vn_valueize (lhs1) == vn_valueize (lhs2); |
| 32 | + } |
| 33 | return operand_equal_p (lhs1, lhs2, 0); |
| 34 | |
| 35 | case GIMPLE_ASSIGN: |
| 36 | lhs1 = gimple_get_lhs (s1); |
| 37 | lhs2 = gimple_get_lhs (s2); |
| 38 | + *gvn_used = true; |
| 39 | return (TREE_CODE (lhs1) == SSA_NAME |
| 40 | && TREE_CODE (lhs2) == SSA_NAME |
| 41 | && vn_valueize (lhs1) == vn_valueize (lhs2)); |
| 42 | @@ -1096,15 +1103,23 @@ gimple_equal_p (same_succ same_succ, gim |
| 43 | case GIMPLE_COND: |
| 44 | t1 = gimple_cond_lhs (s1); |
| 45 | t2 = gimple_cond_lhs (s2); |
| 46 | - if (!operand_equal_p (t1, t2, 0) |
| 47 | - && !gvn_uses_equal (t1, t2)) |
| 48 | - return false; |
| 49 | + if (!operand_equal_p (t1, t2, 0)) |
| 50 | + { |
| 51 | + if (gvn_uses_equal (t1, t2)) |
| 52 | + *gvn_used = true; |
| 53 | + else |
| 54 | + return false; |
| 55 | + } |
| 56 | |
| 57 | t1 = gimple_cond_rhs (s1); |
| 58 | t2 = gimple_cond_rhs (s2); |
| 59 | - if (!operand_equal_p (t1, t2, 0) |
| 60 | - && !gvn_uses_equal (t1, t2)) |
| 61 | - return false; |
| 62 | + if (!operand_equal_p (t1, t2, 0)) |
| 63 | + { |
| 64 | + if (gvn_uses_equal (t1, t2)) |
| 65 | + *gvn_used = true; |
| 66 | + else |
| 67 | + return false; |
| 68 | + } |
| 69 | |
| 70 | code1 = gimple_expr_code (s1); |
| 71 | code2 = gimple_expr_code (s2); |
| 72 | @@ -1126,18 +1141,25 @@ gimple_equal_p (same_succ same_succ, gim |
| 73 | /* Let GSI skip backwards over local defs. */ |
| 74 | |
| 75 | static void |
| 76 | -gsi_advance_bw_nondebug_nonlocal (gimple_stmt_iterator *gsi) |
| 77 | +gsi_advance_bw_nondebug_nonlocal (gimple_stmt_iterator *gsi, tree *vuse) |
| 78 | { |
| 79 | gimple stmt; |
| 80 | + tree lvuse; |
| 81 | |
| 82 | while (true) |
| 83 | { |
| 84 | if (gsi_end_p (*gsi)) |
| 85 | return; |
| 86 | stmt = gsi_stmt (*gsi); |
| 87 | + |
| 88 | + lvuse = gimple_vuse (stmt); |
| 89 | + if (lvuse != NULL_TREE) |
| 90 | + *vuse = lvuse; |
| 91 | + |
| 92 | if (!(is_gimple_assign (stmt) && local_def (gimple_get_lhs (stmt)) |
| 93 | && !gimple_has_side_effects (stmt))) |
| 94 | return; |
| 95 | + |
| 96 | gsi_prev_nondebug (gsi); |
| 97 | } |
| 98 | } |
| 99 | @@ -1146,28 +1168,34 @@ gsi_advance_bw_nondebug_nonlocal (gimple |
| 100 | clusters them. */ |
| 101 | |
| 102 | static void |
| 103 | -find_duplicate (same_succ same_succ, basic_block bb1, basic_block bb2) |
| 104 | +find_duplicate (same_succ same_succ, basic_block bb1, basic_block bb2, |
| 105 | + bool gvn_used) |
| 106 | { |
| 107 | gimple_stmt_iterator gsi1 = gsi_last_nondebug_bb (bb1); |
| 108 | gimple_stmt_iterator gsi2 = gsi_last_nondebug_bb (bb2); |
| 109 | + tree vuse1 = NULL_TREE, vuse2 = NULL_TREE; |
| 110 | |
| 111 | - gsi_advance_bw_nondebug_nonlocal (&gsi1); |
| 112 | - gsi_advance_bw_nondebug_nonlocal (&gsi2); |
| 113 | + gsi_advance_bw_nondebug_nonlocal (&gsi1, &vuse1); |
| 114 | + gsi_advance_bw_nondebug_nonlocal (&gsi2, &vuse2); |
| 115 | |
| 116 | while (!gsi_end_p (gsi1) && !gsi_end_p (gsi2)) |
| 117 | { |
| 118 | - if (!gimple_equal_p (same_succ, gsi_stmt (gsi1), gsi_stmt (gsi2))) |
| 119 | + if (!gimple_equal_p (same_succ, gsi_stmt (gsi1), gsi_stmt (gsi2), |
| 120 | + &gvn_used)) |
| 121 | return; |
| 122 | |
| 123 | gsi_prev_nondebug (&gsi1); |
| 124 | gsi_prev_nondebug (&gsi2); |
| 125 | - gsi_advance_bw_nondebug_nonlocal (&gsi1); |
| 126 | - gsi_advance_bw_nondebug_nonlocal (&gsi2); |
| 127 | + gsi_advance_bw_nondebug_nonlocal (&gsi1, &vuse1); |
| 128 | + gsi_advance_bw_nondebug_nonlocal (&gsi2, &vuse2); |
| 129 | } |
| 130 | |
| 131 | if (!(gsi_end_p (gsi1) && gsi_end_p (gsi2))) |
| 132 | return; |
| 133 | |
| 134 | + if (gvn_used && vuse1 != vuse2) |
| 135 | + return; |
| 136 | + |
| 137 | if (dump_file) |
| 138 | fprintf (dump_file, "find_duplicates: <bb %d> duplicate of <bb %d>\n", |
| 139 | bb1->index, bb2->index); |
| 140 | @@ -1179,7 +1207,7 @@ find_duplicate (same_succ same_succ, bas |
| 141 | E2 are equal. */ |
| 142 | |
| 143 | static bool |
| 144 | -same_phi_alternatives_1 (basic_block dest, edge e1, edge e2) |
| 145 | +same_phi_alternatives_1 (basic_block dest, edge e1, edge e2, bool *gvn_used) |
| 146 | { |
| 147 | int n1 = e1->dest_idx, n2 = e2->dest_idx; |
| 148 | gimple_stmt_iterator gsi; |
| 149 | @@ -1197,7 +1225,10 @@ same_phi_alternatives_1 (basic_block des |
| 150 | if (operand_equal_for_phi_arg_p (val1, val2)) |
| 151 | continue; |
| 152 | if (gvn_uses_equal (val1, val2)) |
| 153 | - continue; |
| 154 | + { |
| 155 | + *gvn_used = true; |
| 156 | + continue; |
| 157 | + } |
| 158 | |
| 159 | return false; |
| 160 | } |
| 161 | @@ -1209,7 +1240,8 @@ same_phi_alternatives_1 (basic_block des |
| 162 | phi alternatives for BB1 and BB2 are equal. */ |
| 163 | |
| 164 | static bool |
| 165 | -same_phi_alternatives (same_succ same_succ, basic_block bb1, basic_block bb2) |
| 166 | +same_phi_alternatives (same_succ same_succ, basic_block bb1, basic_block bb2, |
| 167 | + bool *gvn_used) |
| 168 | { |
| 169 | unsigned int s; |
| 170 | bitmap_iterator bs; |
| 171 | @@ -1227,7 +1259,7 @@ same_phi_alternatives (same_succ same_su |
| 172 | |
| 173 | /* For all phis in bb, the phi alternatives for e1 and e2 need to have |
| 174 | the same value. */ |
| 175 | - if (!same_phi_alternatives_1 (succ, e1, e2)) |
| 176 | + if (!same_phi_alternatives_1 (succ, e1, e2, gvn_used)) |
| 177 | return false; |
| 178 | } |
| 179 | |
| 180 | @@ -1301,6 +1333,7 @@ find_clusters_1 (same_succ same_succ) |
| 181 | bitmap_iterator bi, bj; |
| 182 | int nr_comparisons; |
| 183 | int max_comparisons = PARAM_VALUE (PARAM_MAX_TAIL_MERGE_COMPARISONS); |
| 184 | + bool gvn_used; |
| 185 | |
| 186 | EXECUTE_IF_SET_IN_BITMAP (same_succ->bbs, 0, i, bi) |
| 187 | { |
| 188 | @@ -1333,10 +1366,11 @@ find_clusters_1 (same_succ same_succ) |
| 189 | if (!deps_ok_for_redirect (bb1, bb2)) |
| 190 | continue; |
| 191 | |
| 192 | - if (!(same_phi_alternatives (same_succ, bb1, bb2))) |
| 193 | + gvn_used = false; |
| 194 | + if (!(same_phi_alternatives (same_succ, bb1, bb2, &gvn_used))) |
| 195 | continue; |
| 196 | |
| 197 | - find_duplicate (same_succ, bb1, bb2); |
| 198 | + find_duplicate (same_succ, bb1, bb2, gvn_used); |
| 199 | } |
| 200 | } |
| 201 | } |
| 202 | --- /dev/null |
| 203 | +++ b/testsuite/gcc.dg/pr52734.c |
| 204 | @@ -0,0 +1,35 @@ |
| 205 | +/* { dg-do run } */ |
| 206 | +/* { dg-options "-O2" } */ |
| 207 | + |
| 208 | +int bbb = 0; |
| 209 | + |
| 210 | +int __attribute__((noinline,noclone)) aaa(void) |
| 211 | +{ |
| 212 | + ++bbb; |
| 213 | + return 0; |
| 214 | +} |
| 215 | + |
| 216 | +int __attribute__((noinline,noclone)) ccc(void) |
| 217 | +{ |
| 218 | + int ddd; |
| 219 | + /* bbb == 0 */ |
| 220 | + if (aaa()) |
| 221 | + return bbb; |
| 222 | + |
| 223 | + /* bbb == 1 */ |
| 224 | + ddd = bbb; |
| 225 | + /* bbb == ddd == 1 */ |
| 226 | + if (aaa ()) |
| 227 | + return 0; |
| 228 | + /* bbb == 2, ddd == 1 */ |
| 229 | + |
| 230 | + return ddd; |
| 231 | +} |
| 232 | + |
| 233 | +int main(void) |
| 234 | +{ |
| 235 | + if (ccc() != 1) |
| 236 | + __builtin_abort(); |
| 237 | + return 0; |
| 238 | +} |
| 239 | + |
| 240 | |
