mirror of
https://github.com/Mercury-Language/mercury.git
synced 2026-04-18 19:03:45 +00:00
779e1ce54a
This fixes the general case of Mantis bug 480.
compiler/cse_detection.m:
When deciding whether we want to pull common X = f(...) unifications
out of branched control structures, require only f'a args to be nonunique,
not the args of any other functors that X may be bound to.
compiler/switch_detection.m:
Obey the restrictions that cse_detection.m may impose.
tests/valid/bug480a.m:
A new test case for this bug fix.
tests/valid/Mmakefile:
Enable the new test case.
49 lines
1.3 KiB
Mathematica
49 lines
1.3 KiB
Mathematica
%---------------------------------------------------------------------------%
|
|
% vim: ts=4 sw=4 et ft=mercury
|
|
%---------------------------------------------------------------------------%
|
|
%
|
|
% This is a regression test for a special case of Mantis bug #480.
|
|
%
|
|
% Versions of the Mercury compiler between 2019 Jun 30 and 2019 Aug 7
|
|
% could not compile the correct code of get_g_arg below. The reason was that
|
|
% a fix for github issue 64 applied on Jun 30 prevented cse_detection.m
|
|
% from recognizing that the last two arms of the switch on FG are themselves
|
|
% a switch on the argument of g/1, because the inst of FG contains a unique
|
|
% component, namely the inst of the argument of f/1 (which is irrelevant
|
|
% to whether FG = g(...) can be pulled out of a disjunction).
|
|
%
|
|
%---------------------------------------------------------------------------%
|
|
|
|
:- module bug480a.
|
|
:- interface.
|
|
|
|
:- type sub_g
|
|
---> gs1(int)
|
|
; gs2(int).
|
|
|
|
:- type fg
|
|
---> f(f1 :: int)
|
|
; g(g1 :: sub_g).
|
|
|
|
:- inst u_fg for fg/0
|
|
---> f(unique)
|
|
; g(ground).
|
|
|
|
:- mode u_g_fg == u_fg >> ground.
|
|
|
|
:- pred get_g_arg(fg::u_g_fg, int::out) is det.
|
|
|
|
:- implementation.
|
|
|
|
:- import_module int.
|
|
|
|
get_g_arg(FG, N) :-
|
|
(
|
|
FG = f(_),
|
|
N = 0
|
|
;
|
|
FG = g(gs1(N))
|
|
;
|
|
FG = g(gs2(N))
|
|
).
|