From 7e0c853c6f6a2987ac7616cbfdd52bb41d598bd5 Mon Sep 17 00:00:00 2001 From: Piotr Trojanek Date: Wed, 16 Mar 2022 13:36:40 +0100 Subject: [PATCH] [Ada] Fix expansion of attribute Loop_Entry wrt value propagation When expanding attribute Loop_Entry we create constant object declarations and put them just before the loop. The current values of variables at the point of Loop_Entry attribute must not be used when analysing the initialization expressions of these constants, because they might be different from the values at the loop entry itself. gcc/ada/ * exp_attr.adb (Expand_Loop_Entry_Attribute): Disable value propagation when analysing the constant that holds the Loop_Entry prefix value. --- gcc/ada/exp_attr.adb | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) diff --git a/gcc/ada/exp_attr.adb b/gcc/ada/exp_attr.adb index e6d3e74..daab82f 100644 --- a/gcc/ada/exp_attr.adb +++ b/gcc/ada/exp_attr.adb @@ -26,6 +26,7 @@ with Aspects; use Aspects; with Atree; use Atree; with Checks; use Checks; +with Debug; use Debug; with Einfo; use Einfo; with Einfo.Entities; use Einfo.Entities; with Einfo.Utils; use Einfo.Utils; @@ -1792,23 +1793,30 @@ package body Exp_Attr is Push_Scope (Scope (Loop_Id)); end if; - -- The analysis of the conditional block takes care of the constant - -- declaration. + -- Analyze constant declaration with simple value propagation disabled, + -- because the values at the loop entry might be different than the + -- values at the occurrence of Loop_Entry attribute. - if Present (Result) then - Rewrite (Loop_Stmt, Result); - Analyze (Loop_Stmt); - - -- The conditional block was analyzed when a previous 'Loop_Entry was - -- expanded. There is no point in reanalyzing the block, simply analyze - -- the declaration of the constant. + declare + Save_Debug_Flag_MM : constant Boolean := Debug_Flag_MM; + begin + Debug_Flag_MM := True; - else if Present (Aux_Decl) then Analyze (Aux_Decl); end if; Analyze (Temp_Decl); + + Debug_Flag_MM := Save_Debug_Flag_MM; + end; + + -- If the conditional block has just been created, then analyze it; + -- otherwise it was analyzed when a previous 'Loop_Entry was expanded. + + if Present (Result) then + Rewrite (Loop_Stmt, Result); + Analyze (Loop_Stmt); end if; Rewrite (N, New_Occurrence_Of (Temp_Id, Loc)); -- 2.7.4