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From: bob@tinman.cis.ohio-state.edu (Bob Sutterfield)
Newsgroups: gnu.gcc.bug
Subject: gcc 1.35 float, double bugs on Sun3, Pyramid
Message-ID: <BOB.89Jun27112657@tinman.cis.ohio-state.edu>
Date: 27 Jun 89 15:26:57 GMT
Sender: news@tut.cis.ohio-state.edu
Reply-To: Bob Sutterfield <bob@cis.ohio-state.edu>
Distribution: gnu
Organization: The Ohio State University Dept of Computer & Information Science
Lines: 97

Based on the following thumbnail tests, I'm recommending that our
Sun-3 users invoke gcc with "-O -ffloat-store" and our Pyramid users
avoid "-O".

	/*
	This is a test for floating point arithmetic
	by Douglas Yarrington (yarringt@cis.ohio-state.edu)
	*/

	#include <stdio.h>

	main()
	{
	double	test;
	float	test1;

		test = 3.1415;
		printf("%4.3e\n",3.1415 );
		printf("%f\n", test );
		test1 = 3.1415;
		printf("%f\n", test1 );
	}

compiler	machine		switches	results
--------	-------		--------	-------
Sun CC		Sun3/OS3.5.1			yes
				-O		yes
				-g		yes
GNU CC 1.35	Sun3/OS3.5.1			no
(a)				-g		no
(b)				-O		const & double OK, float bad
				-O -g		const & double OK, float bad
				-ffloat-store	no
				-ff-s -g	no
(c)				-ff-s -O	yes
				-ff-s -O -g	yes
GNU CC 1.26	NeXT/Mach0.9			yes
				-O		yes
				-g		yes
				-O -g		yes
				-ffloat-store	yes
				-ff-s -g	yes
				-ff-s -O	yes
				-ff-s -O -g	yes
Sun CC		Sun4/OS4.0.1			yes
				-O		yes
				-g		yes
GNU CC 1.35	Sun4/OS4.0.1			yes
				-O		yes
				-g		yes
				-O -g		yes
				-ffloat-store	yes
				-ff-s -O	yes
				-ff-s -O -g	yes
				-ff-s -g	yes
Pyramid CC	Pyramid/OSx4.0			yes
				-O		yes
				-OG		yes
				-g		yes
GNU CC 1.35	Pyramid/OSx4.0			yes
				-g		yes
(d)				-O		double OK, const & float diff
				-O -g		double OK, const & float diff
				-ffloat-store	yes
				-ff-s -g	yes
				-ff-s -O	double OK, const & float diff
				-ff-s -O -g	double OK, const & float diff

sample output:

(a) (sun3, gcc -g)
11:02am> ./test-gccg
0.000e+00
0.000000
0.000000
11:02am>

(b) (sun3, gcc -O)
11:03am> ./test-gccO
3.142e+00
3.141500
0.000000
11:03am>

(c) (sun3, gcc -O -gfloat-store) (this is the correct output)
11:03am> ./test-gccOf
3.142e+00
3.141500
3.141500
11:03am>

(d) (pyramid, gcc -O)
11:04am> ./test-gccPO
3.141e+00
3.141500
2.142687
11:04am>