From: Avinash Jayakar <avinashd@linux.ibm.com>
Date: Mon, 13 Oct 2025 09:47:45 +0000 (+0530)
Subject: match.pd: Do not canonicalize division by power 2 for {ROUND, CEIL}_DIV
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=33b1a5d588971079e06a72d86e90b345e6e1cb25;p=thirdparty%2Fgcc.git

match.pd: Do not canonicalize division by power 2 for {ROUND, CEIL}_DIV

Canonicalization of unsigned division by power of 2 only applies to
{TRUNC,FLOOR,EXACT}_DIV, therefore remove the same pattern for {CEIL,ROUND}_DIV,
which was added in a previous commit.

2025-10-13  Avinash Jayakar  <avinashd@linux.ibm.com>

gcc/ChangeLog:
	PR tree-optimization/122213
	* match.pd: Canonicalize unsigned pow2 div only for trunk, floor and
	exact div.
---

diff --git a/gcc/match.pd b/gcc/match.pd
index 4d0a803eaef..41ec9da8aaa 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -981,16 +981,18 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) && TYPE_UNSIGNED (TREE_TYPE (@0)))
   (bit_and @0 (negate @1))))
 
-(for div (trunc_div ceil_div floor_div round_div exact_div)
+/* Canonicalize unsigned t / 4 to t >> 2.  */
 #if GIMPLE
- /* Canonicalize unsigned t / 4 to t >> 2.  */
+(for div (trunc_div floor_div exact_div)
  (simplify
   (div @0 integer_pow2p@1)
   (if (INTEGRAL_TYPE_P (type)
        && (TYPE_UNSIGNED (type) || tree_expr_nonnegative_p (@0)))
    (rshift @0 { build_int_cst (integer_type_node,
-			       wi::exact_log2 (wi::to_wide (@1))); })))
+			       wi::exact_log2 (wi::to_wide (@1))); }))))
 #endif
+
+(for div (trunc_div ceil_div floor_div round_div exact_div)
  /* Simplify (t * u) / u -> t.  */
  (simplify
   (div (mult:c @0 @1) @1)