C compiler incorrectly optimizes XtInstallAccelerators()

[Felix Lee]

Machine Type:   Sun 4/260S
O/S Version:    SunOS 4.0
Organization:   Computer Science Department, The Pennsylvania State University
                333 Whitmore Laboratory, University Park, PA   16802
Phone Number:   +1 814 865 9723

Description:
	The Sun-4 C compiler incorrectly optimizes the function
	XtInstallAccelerators() in the file TMstate.c in the Xt library
	in X11 release 3.

Repeat-By:
	Compile the file with -O and examine the assembly.  Notice that
	it calls XtInitializeStateTable() immediately after calling
	_XtBindAccActions(), which by no stretch of the imagination
	can be considered a correct optimization.

	Relevant code section follows.  For complete source, grab the
	latest X distribution from a random archive/distribution site.

void XtInstallAccelerators(destination,source)
    Widget destination,source;
{
    XtBoundAccActions accBindings;
    if ((!XtIsWindowObject(source)) ||
        source->core.accelerators == NULL) return;
/*    if (source->core.accelerators->accProcTbl == NULL)
 *  %%%
 *  The spec is not clear on when actions specified in accelerators are bound;
 *  The most useful (and easiest) thing seems to be to bind them at this time
 *  (rather than at Realize).  Under the current code the preceeding test
 *  seems always to be True, thus guaranteeing accBindings is always set
 *  before being used below.
 */
        _XtBindAccActions(source,source->core.accelerators,0,&accBindings);
    if (destination->core.tm.translations == NULL) {
        destination->core.tm.translations = source->core.accelerators;
        destination->core.tm.translations->accProcTbl = accBindings;
    }
    else {
        XtTranslations temp;
        _XtInitializeStateTable(&temp);
        temp->clickTime = source->core.accelerators->clickTime;
        if (source->core.accelerators->operation == XtTableOverride) {
            MergeTables(temp,source->core.accelerators,FALSE,accBindings);
            MergeTables(temp, destination->core.tm.translations,FALSE,
                   destination->core.tm.translations->accProcTbl);
        }
        else {
            MergeTables(temp, destination->core.tm.translations,FALSE,
                   destination->core.tm.translations->accProcTbl);
            MergeTables(temp,source->core.accelerators,FALSE,accBindings);
        }
        destination->core.tm.translations = temp;
    }

	[... etc. ]

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--
Felix Lee	flee at shire.cs.psu.edu	*!psuvax1!shire!flee