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+%%% -*- erlang-indent-level: 2 -*-
+%%%-------------------------------------------------------------------
+%%% Author: Kostis Sagonas
+%%%
+%%% Tests the strength reduction component of the HiPE compiler.
+%%%-------------------------------------------------------------------
+-module(basic_strength_reduce).
+
+-export([test/0]).
+%% These functions are exported so as to not remove them by inlining
+-export([crash_0/1, crash_1/1, crash_2/1, crash_3/1, bug_div_2N/1]).
+
+test() ->
+ ok = test_strength_reduce1(),
+ ok.
+
+%%--------------------------------------------------------------------
+
+test_strength_reduce1() ->
+ ok = crash_0(0),
+ ok = crash_1(42),
+ ok = crash_2(42),
+ ok = crash_3(42),
+ 5 = 42 bsr 3 = bug_div_2N(42),
+ -6 = -42 bsr 3 = bug_div_2N(-42) - 1,
+ ok.
+
+%% This is a crash report by Peter Wang (10 July 2007) triggering an
+%% R11B-5 crash: strength reduction could not handle calls with no
+%% destination
+crash_0(A) ->
+ case A of
+ 0 ->
+ A div 8,
+ ok
+ end.
+
+%% The above was simplified to the following which showed another
+%% crash, this time on RTL
+crash_1(A) when is_integer(A), A >= 0 ->
+ A div 8,
+ ok.
+
+%% A similar crash like the first one, but in a different place in the
+%% code, was triggered by the following code
+crash_2(A) when is_integer(A), A >= 0 ->
+ A div 1,
+ ok.
+
+%% A crash similar to the first one happened in the following code
+crash_3(A) ->
+ case A of
+ 42 ->
+ A * 0,
+ ok
+ end.
+
+%% Strength reduction for div/2 and rem/2 with a power of 2
+%% should be performed only for non-negative integers
+bug_div_2N(X) when is_integer(X), X >= 0 ->
+ X div 8;
+bug_div_2N(X) when is_integer(X), X < 0 ->
+ X div 8.
+
+%%--------------------------------------------------------------------