[Webkit-unassigned] [Bug 104376] New: Remove unnecessary float casts in transformations

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=104376

           Summary: Remove unnecessary float casts in transformations
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: WebCore Misc.
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: bfulgham at webkit.org


I recently noticed a number of float casts in the transformation classes. These are likely vestiges from the time with TransformationMatrix.cpp used all float values internally.  This bug cleans up these unnecessary casts to help clarify the meaning of the code.  It may provide a slight performance benefit, as the cast operations on variables requires a couple of additional instructions to convert the data types.  Consider the following two cases, one with the cast in place and the other without:

        mat.m_matrix[1][1] = (float)cosTheta;
5D409F05  fld         qword ptr [cosTheta] 
5D409F08  fstp        dword ptr [ebp-0B0h] 
5D409F0E  fld         dword ptr [ebp-0B0h] 
5D409F14  fstp        qword ptr [ebp-78h] 
        mat.m_matrix[1][2] = sinTheta;
5D409F17  fld         qword ptr [sinTheta] 
5D409F1A  fstp        qword ptr [ebp-70h] 

The double-to-double store is done in two instructions, rather than the four required for the casting case.

-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.