i386: Correct _mm512_mask3_fmaddsub_round_pd

Define _mm512_mask3_fmaddsub_round_pd with
__builtin_ia32_vfmaddsubpd512_mask, instead of
__builtin_ia32_vfmaddpd512_mask.

	PR target/87517
	* config/i386/avx512fintrin.h (_mm512_mask_fmaddsub_round_pd):
	Defined with __builtin_ia32_vfmaddsubpd512_mask.

From-SVN: r264935

gcc/ChangeLog

+2018-10-08  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR target/87517
+	* config/i386/avx512fintrin.h (_mm512_mask_fmaddsub_round_pd):
+	Defined with __builtin_ia32_vfmaddsubpd512_mask.
+
 2018-10-08  Richard Biener  <rguenther@suse.de>
 
 	* config/i386/x86-tune-costs.h (znver1_cost): Make AVX256 vector loads

gcc/config/i386/avx512fintrin.h

@@ -3833,7 +3833,7 @@ _mm512_maskz_fnmsub_round_ps (__mmask16 __U, __m512 __A, __m512 __B,
     (__m512d)__builtin_ia32_vfmaddsubpd512_mask(A, B, C, -1, R)
 
 #define _mm512_mask_fmaddsub_round_pd(A, U, B, C, R)    \
-    (__m512d)__builtin_ia32_vfmaddpd512_mask(A, B, C, U, R)
+    (__m512d)__builtin_ia32_vfmaddsubpd512_mask(A, B, C, U, R)
 
 #define _mm512_mask3_fmaddsub_round_pd(A, B, C, U, R)   \
     (__m512d)__builtin_ia32_vfmaddsubpd512_mask3(A, B, C, U, R)