digitalmars.D.bugs - [Issue 2888] New: [PATCH] float * 2.0 is unnecessarily slow
- d-bugmail puremagic.com (21/21) Apr 24 2009 http://d.puremagic.com/issues/show_bug.cgi?id=2888
- d-bugmail puremagic.com (8/8) Apr 24 2009 http://d.puremagic.com/issues/show_bug.cgi?id=2888
- d-bugmail puremagic.com (10/10) Apr 27 2009 http://d.puremagic.com/issues/show_bug.cgi?id=2888
- d-bugmail puremagic.com (11/11) Jul 09 2009 http://d.puremagic.com/issues/show_bug.cgi?id=2888
http://d.puremagic.com/issues/show_bug.cgi?id=2888 Summary: [PATCH] float * 2.0 is unnecessarily slow Product: D Version: 2.029 Platform: PC OS/Version: Windows Status: NEW Keywords: patch, performance Severity: normal Priority: P2 Component: DMD AssignedTo: bugzilla digitalmars.com ReportedBy: clugdbug yahoo.com.au DMD generates slow code in simple situations such as: double foo(double x) { return x*2; } It creates a floating-point constant 2.0, and then generates an FMUL to multiply by it. It's particularly slow in the 80-bit real case, where two instructions (FLD and FMULP) are required. The attached patch generates the fast and simple FADD ST(0), ST; instead. It only applies to float,double, real, not to complex numbers. --
Apr 24 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2888 Created an attachment (id=338) --> (http://d.puremagic.com/issues/attachment.cgi?id=338&action=view) Patch against DMD2.029 This will be a useful step towards further optimisation of pure functions with real return values. --
Apr 24 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2888 clugdbug yahoo.com.au changed: What |Removed |Added ---------------------------------------------------------------------------- Severity|normal |enhancement Summary|[PATCH] float * 2.0 is |[PATCH] speedup for float * |unnecessarily slow |2.0 Renaming this issue to be less negative --
Apr 27 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2888 Walter Bright <bugzilla digitalmars.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |FIXED 02:48:31 PDT --- Fixed dmd 1.046 and 2.031 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Jul 09 2009