diff options
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/tree-data-ref.c | 45 |
2 files changed, 27 insertions, 24 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f1b0396..f191277 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2004-10-04 Sebastian Pop <pop@cri.ensmp.fr> + + * tree-data-ref.c (array_base_name_differ_p): Fix comments. When + the predicate cannot be computed, don't initialize the result to + false. + 2004-10-01 Eric Christopher <echristo@redhat.com> * dwarf2.h (dwarf_calling_convention): Add GNU prefix to diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c index 8e062d0..5b5905f 100644 --- a/gcc/tree-data-ref.c +++ b/gcc/tree-data-ref.c @@ -96,12 +96,12 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA #include "tree-pass.h" #include "lambda.h" - /* This is the simplest data dependence test: determines whether the - data references A and B access the same array/region. If can't determine - - return false; Otherwise, return true, and DIFFER_P will record - the result. This utility will not be necessary when alias_sets_conflict_p - will be less conservative. */ + data references A and B access the same array/region. Returns + false when the property is not computable at compile time. + Otherwise return true, and DIFFER_P will record the result. This + utility will not be necessary when alias_sets_conflict_p will be + less conservative. */ bool array_base_name_differ_p (struct data_reference *a, @@ -113,17 +113,16 @@ array_base_name_differ_p (struct data_reference *a, tree ta = TREE_TYPE (base_a); tree tb = TREE_TYPE (base_b); - - /** Determine if same base **/ - - /* array accesses: a[i],b[i] or pointer accesses: *a,*b. bases are a,b. */ + /* Determine if same base. Example: for the array accesses + a[i], b[i] or pointer accesses *a, *b, bases are a, b. */ if (base_a == base_b) { *differ_p = false; return true; } - /* pointer based accesses - (*p)[i],(*q)[j]. bases are (*p),(*q) */ + /* For pointer based accesses, (*p)[i], (*q)[j], the bases are (*p) + and (*q) */ if (TREE_CODE (base_a) == INDIRECT_REF && TREE_CODE (base_b) == INDIRECT_REF && TREE_OPERAND (base_a, 0) == TREE_OPERAND (base_b, 0)) { @@ -140,21 +139,21 @@ array_base_name_differ_p (struct data_reference *a, return true; } + /* Determine if different bases. */ - /** Determine if different bases **/ - - /* at this point we know that base_a != base_b. However, pointer accesses - of the form x=(*p) and y=(*q), which bases are p and q, may still by pointing - to the same base. In SSAed GIMPLE p and q will be SSA_NAMES in this case. - Therefore, here we check if it's really two different declarations. */ + /* At this point we know that base_a != base_b. However, pointer + accesses of the form x=(*p) and y=(*q), which bases are p and q, + may still pointing to the same base. In SSAed GIMPLE p and q will + be SSA_NAMES in this case. Therefore, here we check if it's + really two diferent declarations. */ if (TREE_CODE (base_a) == VAR_DECL && TREE_CODE (base_b) == VAR_DECL) { *differ_p = true; return true; } - /* compare two record/union bases s.a and t.b: - s != t or (a != b and s and t are not unions) */ + /* Compare two record/union bases s.a and t.b: s != t or (a != b and + s and t are not unions). */ if (TREE_CODE (base_a) == COMPONENT_REF && TREE_CODE (base_b) == COMPONENT_REF && ((TREE_CODE (TREE_OPERAND (base_a, 0)) == VAR_DECL && TREE_CODE (TREE_OPERAND (base_b, 0)) == VAR_DECL @@ -167,7 +166,7 @@ array_base_name_differ_p (struct data_reference *a, return true; } - /* compare a record/union access and an array access. */ + /* Compare a record/union access and an array access. */ if ((TREE_CODE (base_a) == VAR_DECL && (TREE_CODE (base_b) == COMPONENT_REF && TREE_CODE (TREE_OPERAND (base_b, 0)) == VAR_DECL)) @@ -185,10 +184,9 @@ array_base_name_differ_p (struct data_reference *a, return true; } - /* An insn writing through a restricted pointer is "independent" of any - insn reading or writing through a different pointer, in the same - block/scope. - */ + /* An instruction writing through a restricted pointer is + "independent" of any instruction reading or writing through a + different pointer, in the same block/scope. */ if ((TREE_CODE (ta) == POINTER_TYPE && TYPE_RESTRICT (ta) && !DR_IS_READ(a)) || (TREE_CODE (tb) == POINTER_TYPE && TYPE_RESTRICT (tb) @@ -198,7 +196,6 @@ array_base_name_differ_p (struct data_reference *a, return true; } - *differ_p = false; /* Don't know, but be conservative. */ return false; } |