https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89163
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target| |x86_64-*-*, i?86-*-*
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-02-04
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed. Canonicalization might help to CSE this on the GIMPLE level. The
following doesn't trigger though since we don't fold all stmts during VRP.
diff --git a/gcc/match.pd b/gcc/match.pd
index bccf4df05a2..bdd26a1c53b 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -717,6 +717,13 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
{ tree utype = unsigned_type_for (type); }
(convert (rshift (lshift (convert:utype @0) @2) @3))))))
+(simplify
+ (convert (rshift (convert@2 @0) @1))
+ (if (!TYPE_UNSIGNED (TREE_TYPE (@0))
+ && tree_nop_conversion_p (TREE_TYPE (@2), TREE_TYPE (@0))
+ && tree_expr_nonnegative_p (@0))
+ (convert (rshift @0 @1))))
+
/* Fold (C1/X)*C2 into (C1*C2)/X. */
(simplify
(mult (rdiv@3 REAL_CST@0 @1) REAL_CST@2)
