On Fri, May 31, 2013 at 7:04 AM, Eric Botcazou <ebotca...@adacore.com> wrote: >> I'm okay with most of the change, but I have a question: What happened >> to the unsigned comparisons and LTGT? > > Unsigned comparisons aren't used for FP (the whole block of code is dominated > by a FLOAT_MODE_P (mode) test). LTGT and UNEQ were wrong (but unused) since > they were implemented as NE and EQ respectively and therefore didn't return > the correct result for NaNs. In fact, all the unordered operators were wrong > (but unused) since they were implemented as their ordered counterpart. > >> I'm not going to insist, but this probably deserves an e500-specific >> testcase that it's generating the correct results and not calling >> libgcc for unordered comparisons. > > Note that, for originally unordered comparisons, there has always been a call > to libgcc as rs6000_cbranch_operator is ordered_comparison_operator on e500 > (hence the wrong implementation in rs6000_generate_compare was unused). But, > indeed, we should verify that we don't generate them when the comparisons are > originally ordered, with and without -ftrapping-math. > > I have attached 4 testcases: > - e500-ord-1.c: ordered/signaling predicates, -ftrapping-math > - e500-ord-2.c: ordered/signaling predicates, -fno-trapping-math > - e500-unord-1.c: C99 unordered/quiet predicates, -ftrapping-math > - e500-unord-2.c: C99 unordered/quiet predicates, -fno-trapping-math > > With the unpatched compiler: > - e500-ord-1.c: no calls to __unordsf2 (optimal) > - e500-ord-2.c: calls to __unordsf2 (the very issue I'm fixing) > - e500-unord-1.c: calls to __unordsf2 (optimal) > - e500-unord-2.c: calls to __unordsf2 (useless since -fno-trapping-math) > > With the patched compiler: > - e500-ord-1.c: no calls to __unordsf2 (optimal) > - e500-ord-2.c: no calls to __unordsf2 (optimal) > - e500-unord-1.c: calls to __unordsf2 (optimal) > - e500-unord-2.c: no calls to __unordsf2 (optimal) > > > 2013-05-31 Eric Botcazou <ebotca...@adacore.com> > > * gcc.target/powerpc/e500-ord-1.c: New test. > * gcc.target/powerpc/e500-ord-2.c: Likewise. > * gcc.target/powerpc/e500-unord-1.c: Likewise. > * gcc.target/powerpc/e500-unord-2.c: Likewise.
Great! Thanks for the clarification. Just to be clear, the original patch and the new testcases LGTM. Thanks, David
