Date: Tue, 29 May 2007 22:29:54 -0700 (PDT) From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: FreeBSD-gnats-submit@FreeBSD.org Subject: standards/113147: frexpf in libm has C aliasing issues with gcc 4.2 Message-ID: <200705300529.l4U5Ts3C008014@troutmask.apl.washington.edu> Resent-Message-ID: <200705300540.l4U5e2hn086410@freefall.freebsd.org>
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>Number: 113147 >Category: standards >Synopsis: frexpf in libm has C aliasing issues with gcc 4.2 >Confidential: no >Severity: non-critical >Priority: medium >Responsible: freebsd-standards >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Wed May 30 05:40:02 GMT 2007 >Closed-Date: >Last-Modified: >Originator: Steve Kargl >Release: FreeBSD 7.0-CURRENT amd64 >Organization: apl/uw >Environment: System: FreeBSD troutmask.apl.washington.edu 7.0-CURRENT FreeBSD 7.0-CURRENT #4: Thu Apr 19 12:32:30 PDT 2007 kargl@troutmask.apl.washington.edu:/usr/obj/usr/src/sys/SPEW amd64 >Description: Currently, libm must be built with -fno-strict-aliasing due to undefined behavior according to the C standard. The problem is is s_frexprf.c >How-To-Repeat: Build libm with -fstrict-aliasing in the CFLAGS. >Fix: (Watch for cut-&-paste tab corruption) --- s_frexpf.c.orig Sat May 26 16:26:50 2007 +++ s_frexpf.c Mon May 28 17:55:48 2007 @@ -39,6 +39,6 @@ } *eptr += (ix>>23)-126; hx = (hx&0x807fffff)|0x3f000000; - *(int*)&x = hx; + SET_FLOAT_WORD(x,hx); return x; } >Release-Note: >Audit-Trail: >Unformatted:
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