| Message ID | 20130409072525.7t4cx69hc0os0c08-nzlynne@webmail.spamcop.net |
|---|---|
| State | New |
| Headers | show |
On Tue, Apr 9, 2013 at 1:25 PM, Joern Rennecke <joern.rennecke@embecosm.com> wrote: > Quoting Richard Biener <richard.guenther@gmail.com>: > >> On Mon, Apr 8, 2013 at 5:10 PM, Joern Rennecke >> <joern.rennecke@embecosm.com> wrote: >>> >>> This is basically the same patch as attached to the PR, except that I >>> have changed the goto-loop into a do-while loop with a new comment; >>> this caused the need for a lot of reformatting. >> >> >> Can you please include a testcase that shows the effect of this? > > > Attached. > FWIW, the assembler is simpler to understand if you add the compilation > option -mfp-mode=round-nearest. > Without the patch, you then get: > > _f: > fmul r1,r1,r3 > mov r3, %low(#-2147483648) > movt r3, %high(#-2147483648) > eor r1,r3,r1 > fmadd r1,r0,r2 > mov r0,r1 > rts > > And with the patch: > > _f: > fmul r0,r0,r2 > fmsub r0,r1,r3 > rts This means the iteration doesn't help here. > > >>> 2013-04-08 Joern Rennecke <joern.rennecke@embecosm.com> >>> >>> * tree-ssa-math-opts.c (mult_to_fma_pass): New file static >>> struct. >>> (convert_mult_to_fma): In first pass, don't use an fms construct >>> when we don't have an fms operation, but fmna. >> >> >> it's fnma I believe. > > > Oops, yes, typo. The patch itself has the right spelling. > > 2013-03-09 Joern Rennecke <joern.rennecke@embecosm.com> > > * gcc.target/epiphany/fnma-1.c: New test. > > Index: gcc.target/epiphany/fnma-1.c > =================================================================== > --- gcc.target/epiphany/fnma-1.c (revision 0) > +++ gcc.target/epiphany/fnma-1.c (working copy) > @@ -0,0 +1,9 @@ > +/* { dg-do compile } */ > +/* { dg-options "-O2" } */ > +/* { dg-final { scan-assembler-times "fmsub\[ \ta-zA-Z0-9\]*," 1 } } */ > + > +float > +f (float ar, float ai, float br, float bi) > +{ > + return ar * br - ai * bi; > +} >
Index: gcc.target/epiphany/fnma-1.c =================================================================== --- gcc.target/epiphany/fnma-1.c (revision 0) +++ gcc.target/epiphany/fnma-1.c (working copy) @@ -0,0 +1,9 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ +/* { dg-final { scan-assembler-times "fmsub\[ \ta-zA-Z0-9\]*," 1 } } */ + +float +f (float ar, float ai, float br, float bi) +{ + return ar * br - ai * bi; +}