| Message ID | 5523688.bpAWfy1Iex@polaris |
|---|---|
| State | New |
| Headers | show |
| Series | Do not generate libcalls to __unord[sd]f2 on PowerPC SPE | expand |
On Fri, Feb 9, 2018 at 11:28 AM, Eric Botcazou <ebotcazou@adacore.com> wrote: > Hi, > > the change > > 2016-05-02 Marc Glisse <marc.glisse@inria.fr> > > * match.pd (X u< X, X u> X): New transformations. > > has an annoying effect on targets implementing (most) unordered comparisons in > hardware but not the UNORDERED operator itself, e.g. PowerPC SPE, because it > makes the compiler generate unnecessary libcalls to __unord[sd]f2. > > The attached patch contains a trick to undo the effect of the change at the > RTL level for such targets. It was tested on PowerPC SPE with a certified > version of VxWorks (which provides a minimal certified libgcc) where it fixes > the link failure of ACATS c45242b with optimization enabled. > > OK for the mainline? Ok. Richard. > > 2018-02-09 Eric Botcazou <ebotcazou@adacore.com> > > * optabs.c (prepare_cmp_insn): Try harder to emit a direct comparison > instead of a libcall for UNORDERED. > > -- > Eric Botcazou
Index: optabs.c =================================================================== --- optabs.c (revision 257404) +++ optabs.c (working copy) @@ -3935,7 +3935,20 @@ prepare_cmp_insn (rtx x, rtx y, enum rtx if (methods != OPTAB_LIB_WIDEN) goto fail; - if (!SCALAR_FLOAT_MODE_P (mode)) + if (SCALAR_FLOAT_MODE_P (mode)) + { + /* Small trick if UNORDERED isn't implemented by the hardware. */ + if (comparison == UNORDERED && rtx_equal_p (x, y)) + { + prepare_cmp_insn (x, y, UNLT, NULL_RTX, unsignedp, OPTAB_WIDEN, + ptest, pmode); + if (*ptest) + return; + } + + prepare_float_lib_cmp (x, y, comparison, ptest, pmode); + } + else { rtx result; machine_mode ret_mode; @@ -3982,8 +3995,6 @@ prepare_cmp_insn (rtx x, rtx y, enum rtx prepare_cmp_insn (x, y, comparison, NULL_RTX, unsignedp, methods, ptest, pmode); } - else - prepare_float_lib_cmp (x, y, comparison, ptest, pmode); return;