On Tue, 18 Jul 2017, Jakub Jelinek wrote:
+/* X / C1 op C2 into a simple range test. */
+(for cmp (simple_comparison)
+ (simplify
+ (cmp (trunc_div:s @0 INTEGER_CST@1) INTEGER_CST@2)
+ (if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
+ && integer_nonzerop (@1)
+ && !TREE_OVERFLOW (@1)
+ && !TREE_OVERFLOW (@2))
(not specific to this patch)
I wonder if we should check TREE_OVERFLOW for the input that way in many
more transformations in match.pd, or never, or how to decide in which
cases to do it...
+ (with { tree lo, hi; bool neg_overflow;
+ enum tree_code code = fold_div_compare (cmp, @1, @2, &lo, &hi,
+ &neg_overflow); }
+ (switch
+ (if (code == LT_EXPR || code == GE_EXPR)
+ (if (TREE_OVERFLOW (lo))
+ { build_int_cst (type, (code == LT_EXPR) ^ neg_overflow); }
+ (if (code == LT_EXPR)
+ (lt @0 { lo; })
+ (ge @0 { lo; }))))
+ (if (code == LE_EXPR || code == GT_EXPR)
+ (if (TREE_OVERFLOW (hi))
+ { build_int_cst (type, (code == LE_EXPR) ^ neg_overflow); }
+ (if (code == LE_EXPR)
+ (le @0 { hi; })
+ (gt @0 { hi; }))))
+ (if (!lo && !hi)
+ { build_int_cst (type, code == NE_EXPR); })
+ (if (code == EQ_EXPR && !hi)
+ (ge @0 { lo; }))
+ (if (code == EQ_EXPR && !lo)
+ (le @0 { hi; }))
+ (if (code == NE_EXPR && !hi)
+ (lt @0 { lo; }))
+ (if (code == NE_EXPR && !lo)
+ (gt @0 { hi; }))
+ (if (GENERIC)
+ { build_range_check (UNKNOWN_LOCATION, type, @0, code == EQ_EXPR,
+ lo, hi); })
+ (with
+ {
+ tree etype = range_check_type (TREE_TYPE (@0));
+ if (etype)
+ {
+ if (! TYPE_UNSIGNED (etype))
+ etype = unsigned_type_for (etype);
Now that you enforce unsignedness, can you think of cases where going
through range_check_type is useful compared to
tree etype = unsigned_type_for (TREE_TYPE (@0));
? I can propose that trivial patch as a follow-up if you like.
+ hi = fold_convert (etype, hi);
+ lo = fold_convert (etype, lo);
+ hi = const_binop (MINUS_EXPR, etype, hi, lo);
+ }
+ }
+ (if (etype && hi && !TREE_OVERFLOW (hi))
I don't think you can have an overflow here anymore, now that etype is
always unsigned and since you check the input (doesn't hurt though).
+ (if (code == EQ_EXPR)
+ (le (minus (convert:etype @0) { lo; }) { hi; })
+ (gt (minus (convert:etype @0) { lo; }) { hi; })))))))))
--
Marc Glisse
