commit 36c17c7079a5243a890ba43affff326a041775a9

Author: Paul A. Clarke <pc@us.ibm.com>

Date:   Thu Sep 19 11:31:31 2019 -0500

    [powerpc] libc_feholdsetround_noex_ppc_ctx: optimize FPSCR write

    libc_feholdsetround_noex_ppc_ctx currently performs:

    1. Read FPSCR, save to context.

    2. Create new FPSCR value: clear enables and set new rounding mode.

    3. Write new value to FPSCR.

    Since other bits just pass through, there is no need to write them.

    Instead, write just the changed values (enables and rounding mode),

    which can be a bit more efficient.

diff --git a/sysdeps/powerpc/fpu/fenv_private.h b/sysdeps/powerpc/fpu/fenv_private.h

index 86a3611b3ef41759..c88142fe3053580f 100644

--- a/sysdeps/powerpc/fpu/fenv_private.h

+++ b/sysdeps/powerpc/fpu/fenv_private.h

@@ -142,7 +142,7 @@ libc_feholdsetround_noex_ppc_ctx (struct rm_ctx *ctx, int r)

   if (__glibc_unlikely (new.l != old.l))

     {

       __TEST_AND_ENTER_NON_STOP (old.l, 0ULL);

-      fesetenv_register (new.fenv);

+      fesetenv_mode (new.fenv);

       ctx->updated_status = true;

     }

   else