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authorPaul A. Clarke <pc@us.ibm.com>2019-09-19 11:39:44 -0500
committerPaul A. Clarke <pc@us.ibm.com>2019-09-27 08:53:01 -0500
commite68b1151f7460d5fa88c3a567c13f66052da79a7 (patch)
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[powerpc] __fesetround_inline optimizations
On POWER9, use more efficient means to update the 2-bit rounding mode
via the 'mffscrn' instruction (instead of two 'mtfsb0/1' instructions
or one 'mtfsfi' instruction that modifies 4 bits).

Suggested-by: Paul E. Murphy  <murphyp@linux.ibm.com>
Reviewed-By: Paul E Murphy <murphyp@linux.ibm.com>
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@@ -1,5 +1,11 @@
 2019-09-27  Paul A. Clarke  <pc@us.ibm.com>
 
+	* sysdeps/powerpc/fpu/fenv_libc.h (__fesetround_inline): Use
+	'mffscrn' instruction on POWER9.
+	(__fesetround_inline_nocheck): Likewise.
+
+2019-09-27  Paul A. Clarke  <pc@us.ibm.com>
+
 	* sysdeps/powerpc/fpu/fenv_libc.h (FPSCR_EXCEPTIONS_MASK):  New.
 	* sysdeps/powerpc/fpu/fenv_private.h (__libc_femergeenv_ppc):  Optimize
 	to write FPSCR control only, if exceptions have not changed.