From 5c63fd2c90405ce32a229ebadfea96e46413ec88 Mon Sep 17 00:00:00 2001 From: Eric Botcazou Date: Wed, 20 May 2020 10:13:05 +0200 Subject: [PATCH] [Ada] Add comment on implementation choice for byte-packed array types gcc/ada/ * freeze.adb (Freeze_Array_Type): Add comment on implementation choice for byte-packed array types. --- gcc/ada/freeze.adb | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/gcc/ada/freeze.adb b/gcc/ada/freeze.adb index cb32f9d3c13..528a7dd8718 100644 --- a/gcc/ada/freeze.adb +++ b/gcc/ada/freeze.adb @@ -2928,7 +2928,10 @@ package body Freeze is -- Bit packing is not needed for multiples of the storage -- unit if the type is composite because the back end can - -- byte pack composite types. + -- byte pack composite types efficiently. That's not true + -- for discrete types because every read would generate a + -- lot of instructions, so we keep using the manipulation + -- routines of the runtime for them. elsif Csiz mod System_Storage_Unit = 0 and then Is_Composite_Type (Ctyp) -- 2.30.2