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author | Eric Botcazou <ebotcazou@adacore.com> | 2019-02-26 10:55:16 +0000 |
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committer | Eric Botcazou <ebotcazou@gcc.gnu.org> | 2019-02-26 10:55:16 +0000 |
commit | cf02f8a350498eed424aea4a2fff2cbfd646fd61 (patch) | |
tree | 82781cd998e8f5d9e4ddbbaf5ac556568adb6752 /gcc/tree-ssa-dom.c | |
parent | 0eaf141239b27fa96c41558eab8f5ffba70bed4e (diff) | |
download | gcc-cf02f8a350498eed424aea4a2fff2cbfd646fd61.zip gcc-cf02f8a350498eed424aea4a2fff2cbfd646fd61.tar.gz gcc-cf02f8a350498eed424aea4a2fff2cbfd646fd61.tar.bz2 |
opt77.adb: New test.
* gnat.dg/opt77.adb: New test.
* gnat.dg/opt77_pkg.ad[sb]: New helper.
From-SVN: r269208
Diffstat (limited to 'gcc/tree-ssa-dom.c')
-rw-r--r-- | gcc/tree-ssa-dom.c | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c index 12647e7..4f4b7db 100644 --- a/gcc/tree-ssa-dom.c +++ b/gcc/tree-ssa-dom.c @@ -170,11 +170,10 @@ edge_info::derive_equivalences (tree name, tree value, int recursion_limit) gimple *def_stmt = SSA_NAME_DEF_STMT (name); if (is_gimple_assign (def_stmt)) { - /* We know the result of DEF_STMT was zero. See if that allows - us to deduce anything about the SSA_NAMEs used on the RHS. */ enum tree_code code = gimple_assign_rhs_code (def_stmt); switch (code) { + /* If the result of an OR is zero, then its operands are, too. */ case BIT_IOR_EXPR: if (integer_zerop (value)) { @@ -188,8 +187,7 @@ edge_info::derive_equivalences (tree name, tree value, int recursion_limit) } break; - /* We know the result of DEF_STMT was one. See if that allows - us to deduce anything about the SSA_NAMEs used on the RHS. */ + /* If the result of an AND is nonzero, then its operands are, too. */ case BIT_AND_EXPR: if (!integer_zerop (value)) { @@ -296,7 +294,6 @@ edge_info::derive_equivalences (tree name, tree value, int recursion_limit) break; } - case EQ_EXPR: case NE_EXPR: { @@ -336,7 +333,28 @@ edge_info::derive_equivalences (tree name, tree value, int recursion_limit) case NEGATE_EXPR: { tree rhs = gimple_assign_rhs1 (def_stmt); - tree res = fold_build1 (code, TREE_TYPE (rhs), value); + tree res; + /* If this is a NOT and the operand has a boolean range, then we + know its value must be zero or one. We are not supposed to + have a BIT_NOT_EXPR for boolean types with precision > 1 in + the general case, see e.g. the handling of TRUTH_NOT_EXPR in + the gimplifier, but it can be generated by match.pd out of + a BIT_XOR_EXPR wrapped in a BIT_AND_EXPR. Now the handling + of BIT_AND_EXPR above already forces a specific semantics for + boolean types with precision > 1 so we must do the same here, + otherwise we could change the semantics of TRUTH_NOT_EXPR for + boolean types with precision > 1. */ + if (code == BIT_NOT_EXPR + && TREE_CODE (rhs) == SSA_NAME + && ssa_name_has_boolean_range (rhs)) + { + if (integer_zerop (value)) + res = build_one_cst (TREE_TYPE (rhs)); + else + res = build_zero_cst (TREE_TYPE (rhs)); + } + else + res = fold_build1 (code, TREE_TYPE (rhs), value); derive_equivalences (rhs, res, recursion_limit - 1); break; } |