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Re: [Ada] Ensure consistency of fpt exponentiation results
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Arnaud Charlet <charlet at adacore dot com>, Robert Dewar <dewar at adacore dot com>
- Date: Tue, 26 May 2015 22:19:15 +0200
- Subject: Re: [Ada] Ensure consistency of fpt exponentiation results
- Authentication-results: sourceware.org; auth=none
- References: <20150526103520 dot GA27917 at adacore dot com>
> This change ensures on all targets that A**B = A**C when B is a small
> static constant in the range 0 .. 4 and C is a variable with the same
> value. Previously for Float and Long_Float on some targets, this was
> not the case. The results given were both within the error bounds that
> are allowed by the Ada standard, but it is desirable not to have this
> discrepancy.
This uncovered a bug in gigi, responsible for
=== acats tests ===
FAIL: c44003d
Fixed thusly, tested on x86_64-suse-linux, applied on the mainline.
2015-05-26 Eric Botcazou <ebotcazou@adacore.com>
* gcc-interface/trans.c (Attribute_to_gnu) <Attr_Machine>: Do not apply
extra-precision trick to literals. Build SAVE_EXPR manually.
--
Eric BotcazouIndex: gcc-interface/trans.c
===================================================================
--- gcc-interface/trans.c (revision 223709)
+++ gcc-interface/trans.c (working copy)
@@ -2428,7 +2428,8 @@ Attribute_to_gnu (Node_Id gnat_node, tre
gnu_result_type = get_unpadded_type (Etype (gnat_node));
gnu_result = convert (gnu_result_type, gnu_expr);
- if (fp_arith_may_widen
+ if (TREE_CODE (gnu_result) != REAL_CST
+ && fp_arith_may_widen
&& TYPE_PRECISION (gnu_result_type)
< TYPE_PRECISION (longest_float_type_node))
{
@@ -2441,7 +2442,7 @@ Attribute_to_gnu (Node_Id gnat_node, tre
finish_record_type (rec_type, field, 0, false);
rec_val = build_constructor_single (rec_type, field, gnu_result);
- rec_val = save_expr (rec_val);
+ rec_val = build1 (SAVE_EXPR, rec_type, rec_val);
asm_expr
= build5 (ASM_EXPR, void_type_node,