The simple reason may be F8 is the largest type for sqrt.
Another solution may be to set the type to the operand. But I simply want to
make it consistent to other intrinsics with similar issue (they solve it in
this way).
Best Regards,
yiran
On Fri, Sep 10, 2010 at 3:14 PM, Sun Chan <sun.c...@gmail.com> wrote:
> why is F8 the default, but not others?
> Sun
>
> On Sat, Sep 11, 2010 at 6:08 AM, Yiran Wang <yiran.w...@gmail.com> wrote:
> > Hi Sun,
> > Sure.
> > The situation is as following.
> > There is implementation of the intrinsic "sqrt", for a number of types,
> such
> > as F4, F8, and so on. While, the compiler want to determine the exact
> type
> > of the sqrt by context. For example,
> > double a, b;
> > a = sqrt(b);
> > Then the type is F8.
> > Usually it works, but for the following code:
> > double x;
> > int y;
> > y = sqrt(x*x)>1?1:0;
> > The result of sqrt is used by the > operator. While, the operator > would
> > like to promote the type of the two operands, so they match. So it would
> not
> > provide type information for the sqrt intrinsic. So, the compiler simply
> > generate something like
> > VSTID...
> > VSQRT ...
> > The change is to set default type to F8, for such case.
> > Best Regards,
> > yiran
> >
> > On Fri, Sep 10, 2010 at 2:54 PM, Sun Chan <sun.c...@gmail.com> wrote:
> >>
> >> please give a brief description of the bug. Or a simple test case. The
> >> portion of code change is not enough for me to tell why F8 is the
> >> right type, but not, say, F4, or V8....
> >> Sun
> >>
> >> On Sat, Sep 11, 2010 at 2:58 AM, Yiran Wang <yiran.w...@gmail.com>
> wrote:
> >> > Hi All,
> >> > Could a gatekeeper please review it?
> >> > Simply, the ret_mtype should be reset automatically, if it is void.
> This
> >> > is
> >> > already done for a number of other intrinsics.
> >> > The bug is triggered when the combination of > and ?: operator is
> used,
> >> > as
> >> > the result type is not set by parent of the intrinsic.
> >> > Best Regards,
> >> > yiran
> >> >
> >> > Index: wgen_expr.cxx
> >> > ===================================================================
> >> > --- wgen_expr.cxx (revision 3338)
> >> > +++ wgen_expr.cxx (working copy)
> >> > @@ -8153,6 +8153,7 @@
> >> > #ifndef TARG_MIPS // MIPS needs quad emulation for sqrt operation
> >> > case GSBI_BUILT_IN_SQRTL:
> >> > #endif
> >> > + if (ret_mtype == MTYPE_V) ret_mtype = MTYPE_F8;
> >> > if (! gs_flag_errno_math(program)) {
> >> > arg_wn = WGEN_Expand_Expr (gs_tree_value
> >> > (gs_tree_operand
> >> > (exp, 1)));
> >> > wn = WN_CreateExp1 (OPR_SQRT, ret_mtype, MTYPE_V,
> >> > arg_wn);
> >> >
> >> >
> >> >
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> >> >
> >
> >
>
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