https://gcc.gnu.org/g:907b5fe73445f04545a21ecfb522fc0b6388ae99
commit 907b5fe73445f04545a21ecfb522fc0b6388ae99
Author: Mikael Morin <mik...@gcc.gnu.org>
Date: Thu May 8 21:42:53 2025 +0200
Correction régression reassoc_6
Diff:
---
gcc/match.pd | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/gcc/match.pd b/gcc/match.pd
index 4d7fa10a18df..ab8250fc2b8b 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -832,6 +832,30 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(rshift (convert @0)
{ build_int_cst (integer_type_node,
wi::exact_log2 (wi::to_wide (@2))); }))))
+(for div (trunc_div ceil_div floor_div round_div exact_div rshift)
+ (for mul (mult lshift)
+ (simplify (div (mul @0 INTEGER_CST@1) INTEGER_CST@2)
+ (with
+ {wide_int cst1, cst2;
+ if (mul == LSHIFT_EXPR)
+ cst1 = wi::lshift (wi::one (TYPE_PRECISION (type)), wi::to_wide (@1));
+ else
+ cst1 = wi::to_wide (@1);
+ if (div == RSHIFT_EXPR)
+ cst2 = wi::lshift (wi::one (TYPE_PRECISION (type)), wi::to_wide (@2));
+ else
+ cst2 = wi::to_wide (@2);}
+ (switch
+ (if (cst1 == cst2) @0)
+ (if (wi::multiple_of_p (cst1, cst2, TYPE_SIGN (type)))
+ (mul @0 { wide_int_to_tree (type,
+ wi::div_trunc (cst1, cst2,
+ TYPE_SIGN (type))); }))
+ (if (wi::multiple_of_p (cst2, cst1, TYPE_SIGN (type)))
+ (div @0 { wide_int_to_tree (type,
+ wi::div_trunc (cst2, cst1,
+ TYPE_SIGN (type))); })))))))
+
/* If ARG1 is a constant, we can convert this to a multiply by the
reciprocal. This does not have the same rounding properties,
