From 55cb8c5c9abfe83c342a7b8e8b7dd4bee1791302 Mon Sep 17 00:00:00 2001
From: Eric Botcazou <ebotcazou@adacore.com>
Date: Tue, 22 Nov 2022 19:03:49 +0100
Subject: [PATCH] Fix wrong array type conversion with different storage orde
When two arrays of scalars have a different storage order in Ada, the
front-end makes sure that the conversion is performed component-wise
so that each component can be reversed. So it's a little bit counter
productive that the ldist pass performs the opposite transformation
and synthesizes a memcpy/memmove in this case.
gcc/
* tree-loop-distribution.cc (loop_distribution::classify_builtin_ldst):
Bail out if source and destination do not have the same storage order.
gcc/testsuite/
* gnat.dg/sso18.adb: New test.
---
gcc/testsuite/gnat.dg/sso18.adb | 21 +++++++++++++++++++++
gcc/tree-loop-distribution.cc | 7 ++++++-
2 files changed, 27 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gnat.dg/sso18.adb
diff --git a/gcc/testsuite/gnat.dg/sso18.adb b/gcc/testsuite/gnat.dg/sso18.adb
new file mode 100644
index 000000000000..7496e965fd33
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/sso18.adb
@@ -0,0 +1,21 @@
+-- { dg-do run }
+-- { dg-options "-O2" }
+
+with System;
+
+procedure SSO18 is
+
+ type Arr is array (1..32) of Short_Integer;
+ type Rev_Arr is array (1..32) of Short_Integer
+ with Scalar_Storage_Order => System.High_Order_First;
+ C : constant Arr := (others => 16);
+ RA : Rev_Arr;
+ A : Arr;
+
+begin
+ RA := Rev_Arr(C);
+ A := Arr (RA);
+ if A /= C or else RA(1) /= 16 then
+ raise Program_Error;
+ end if;
+end;
diff --git a/gcc/tree-loop-distribution.cc b/gcc/tree-loop-distribution.cc
index ed3dd73e1a96..15ae24108615 100644
--- a/gcc/tree-loop-distribution.cc
+++ b/gcc/tree-loop-distribution.cc
@@ -1790,10 +1790,15 @@ loop_distribution::classify_builtin_ldst (loop_p loop, struct graph *rdg,
if (res != 2)
return;
- /* They much have the same access size. */
+ /* They must have the same access size. */
if (!operand_equal_p (size, src_size, 0))
return;
+ /* They must have the same storage order. */
+ if (reverse_storage_order_for_component_p (DR_REF (dst_dr))
+ != reverse_storage_order_for_component_p (DR_REF (src_dr)))
+ return;
+
/* Load and store in loop nest must access memory in the same way, i.e,
their must have the same steps in each loop of the nest. */
if (dst_steps.length () != src_steps.length ())
--
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