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[Ada] Fix wrong number of iterations for specific loop
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Tue, 13 Aug 2013 18:03:41 +0200
- Subject: [Ada] Fix wrong number of iterations for specific loop
This is a regression present on all the active branches. The compiler
generates code that doesn't execute the expected number of iterations for a
loop with a dynamic upper bound whose value is exactly the upper bound of the
base index type and is obtained through a narrowing conversion.
Tested on x86_64-suse-linux, applied on all the active branches.
2013-08-13 Eric Botcazou <ebotcazou@adacore.com>
* gcc-interface/trans.c (can_equal_min_or_max_val_p): Be prepared for
values outside of the range of the type.
2013-08-13 Eric Botcazou <ebotcazou@adacore.com>
* gnat.dg/loop_optimization16.adb: New test.
* gnat.dg/loop_optimization16_pkg.ad[sb]: New helper.
--
Eric Botcazou
Index: gcc-interface/trans.c
===================================================================
--- gcc-interface/trans.c (revision 201622)
+++ gcc-interface/trans.c (working copy)
@@ -2391,7 +2391,10 @@ can_equal_min_or_max_val_p (tree val, tr
if (TREE_CODE (val) != INTEGER_CST)
return true;
- return tree_int_cst_equal (val, min_or_max_val) == 1;
+ if (max)
+ return tree_int_cst_lt (val, min_or_max_val) == 0;
+ else
+ return tree_int_cst_lt (min_or_max_val, val) == 0;
}
/* Return true if VAL (of type TYPE) can equal the minimum value of TYPE.
-- { dg-do run }
with Loop_Optimization16_Pkg; use Loop_Optimization16_Pkg;
procedure Loop_Optimization16 is
Counter : Natural := 0;
C : constant Natural := F;
subtype Index_T is Index_Base range 1 .. Index_Base (C);
begin
for I in Index_T'First .. Index_T'Last loop
Counter := Counter + 1;
exit when Counter > 200;
end loop;
if Counter > 200 then
raise Program_Error;
end if;
end Loop_Optimization16;
package body Loop_Optimization16_Pkg is
function F return Natural is
begin
return Natural (Index_Base'Last);
end;
end Loop_Optimization16_Pkg;
package Loop_Optimization16_Pkg is
type Index_Base is range 0 .. 127;
function F return Natural;
end Loop_Optimization16_Pkg;