[multiple changes]

2012-10-02  Robert Dewar  <dewar@adacore.com>

	* sem_dim.adb: Minor code reorganization.
	* sem_dim.ads: Add comment.

2012-10-02  Robert Dewar  <dewar@adacore.com>

	* checks.ads, exp_ch4.adb, checks.adb
	(Minimize_Eliminate_Overflow_Checks): Add Top_Level parameter to avoid
	unnecessary conversions to Bignum.
	Minor reformatting.

2012-10-02  Ed Schonberg  <schonberg@adacore.com>

	* sem_ch6.adb (Process_PPCs): Generate invariant checks for a
	return value whose type is an access type and whose designated
	type has invariants. Ditto for in-out parameters and in-parameters
	of an access type.
	* exp_ch3.adb (Build_Component_Invariant_Call): Add invariant check
	for an access component whose designated type has invariants.

From-SVN: r191956

1 files changed, 14 insertions, 3 deletions

diff --git a/gcc/ada/checks.ads b/gcc/ada/checks.ads
index 9fd8034..583d558 100644
--- a/gcc/ada/checks.ads
+++ b/gcc/ada/checks.ads
@@ -260,9 +260,10 @@ package Checks is
    --  parameter is used to supply Sloc values for the constructed tree.
 
    procedure Minimize_Eliminate_Overflow_Checks
-     (N  : Node_Id;
-      Lo : out Uint;
-      Hi : out Uint);
+     (N         : Node_Id;
+      Lo        : out Uint;
+      Hi        : out Uint;
+      Top_Level : Boolean);
    --  This is the main routine for handling MINIMIZED and ELIMINATED overflow
    --  checks. On entry N is a node whose result is a signed integer subtype.
    --  If the node is an artihmetic operation, then a range analysis is carried
@@ -321,6 +322,16 @@ package Checks is
    --
    --  Note that if Bignum values appear, the caller must take care of doing
    --  the appropriate mark/release operation on the secondary stack.
+   --
+   --  Top_Level is used to avoid inefficient unnecessary transitions into the
+   --  Bignum domain. If Top_Level is True, it means that the caller will have
+   --  to convert any Bignum value back to Long_Long_Integer, checking that the
+   --  value is in range. This is the normal case for a top level operator in
+   --  a subexpression. There is no point in going into Bignum mode to avoid an
+   --  overflow just so we can check for overflow the next moment. For calls
+   --  from comparisons and membership tests, and for all recursive calls, we
+   --  do want to transition into the Bignum domain if necessary. Note that
+   --  this setting is only relevant in ELIMINATED mode.
 
    -------------------------------------------------------
    -- Control and Optimization of Range/Overflow Checks --