Path: utzoo!utgpu!watmath!uunet!tut.cis.ohio-state.edu!mailrus!eecae!cps3xx!rang From: rang@cpsin3.cps.msu.edu (Anton Rang) Newsgroups: gnu.gcc.bug Subject: Floating-point constants lose on Sun-3 (GCC 1.31) Summary: Constants which are too large assemble (incorrectly) to "Infinity" Message-ID: <1208@cps3xx.UUCP> Date: 1 Dec 88 02:10:37 GMT Sender: usenet@cps3xx.UUCP Reply-To: rang@cpswh.cps.msu.edu (Anton Rang) Organization: Michigan State University, Computer Science Dept. Lines: 31 On a Sun-3/280 (SunOS 3.4, GCC 1.31) the following program can generate bad assembly code. A warning message is produced (x.c:7: warning: floating point number exceeds range of `double') but the generated code is wrong with optimization on. #includemain() { float f; f = HUGE; /* Defined by Sun to be 99.e999 */ printf("%f\n", f); } Without optimization, the constant is stored in memory as: .long 0x7f800000 which is (correctly) IEEE "infinity". With optimization, this is integrated into an "fmoves" instruction; apparently, a printf() or similar call is used to format it, and the result is: fmoves #0rInfinity,fp0 which the assembler rejects. +---------------------------+------------------------+----------------------+ | Anton Rang (grad student) | "VMS Forever!" | "Do worry...be SAD!" | | Michigan State University | rang@cpswh.cps.msu.edu | | +---------------------------+------------------------+----------------------+