[PATCH v2] [x86] Fix incorrect _mm_cvtsbh_ss.

[liuhongt <hongtao.liu@intel.com>]

After supporting real __bf16, the implementation of _mm_cvtsbh_ss went
wrong.

The patch add a builtin to generate pslld for the intrinsic, also
extendbfsf2 is supported with pslld when !flag_signaling_nans &&
!HONOR_NANS (BFmode).

truncsfbf2 is supported with vcvtneps2bf16 when !flag_signaling_nans &&
!HONOR_NANS (BFmode) && flag_unsafe_math_optimizations.

Here's updated patch.
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}
Ok for trunk?

gcc/ChangeLog:

	PR target/107748
	* config/i386/avx512bf16intrin.h (_mm_cvtsbh_ss): Refined.
	* config/i386/i386-builtin-types.def (FLOAT_FTYPE_BFLOAT16):
	New function type.
	* config/i386/i386-builtin.def (BDESC): New builtin.
	* config/i386/i386-expand.cc (ix86_expand_args_builtin):
	Handle the builtin.
	* config/i386/i386.md (extendbfsf2): New expander.
	(extendbfsf2_1): New define_insn.
	(truncsfbf2): Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/avx512bf16-cvtsbh2ss-1.c: Scan pslld.
	* gcc.target/i386/extendbfsf.c: New test.
---
 gcc/config/i386/avx512bf16intrin.h            |  4 +-
 gcc/config/i386/i386-builtin-types.def        |  1 +
 gcc/config/i386/i386-builtin.def              |  2 +
 gcc/config/i386/i386-expand.cc                |  1 +
 gcc/config/i386/i386.md                       | 41 ++++++++++++++++++-
 .../gcc.target/i386/avx512bf16-cvtsbh2ss-1.c  |  3 +-
 gcc/testsuite/gcc.target/i386/extendbfsf.c    | 16 ++++++++
 7 files changed, 62 insertions(+), 6 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/extendbfsf.c

diff --git a/gcc/config/i386/avx512bf16intrin.h b/gcc/config/i386/avx512bf16intrin.h
index ea1d0125b3f..75378af5584 100644
--- a/gcc/config/i386/avx512bf16intrin.h
+++ b/gcc/config/i386/avx512bf16intrin.h
@@ -46,9 +46,7 @@ extern __inline float
 __attribute__ ((__gnu_inline__, __always_inline__, __artificial__))
 _mm_cvtsbh_ss (__bf16 __A)
 {
-  union{ float a; unsigned int b;} __tmp;
-  __tmp.b = ((unsigned int)(__A)) << 16;
-  return __tmp.a;
+  return __builtin_ia32_cvtbf2sf (__A);
 }
 
 /* vcvtne2ps2bf16 */
diff --git a/gcc/config/i386/i386-builtin-types.def b/gcc/config/i386/i386-builtin-types.def
index d10de32643f..65fe070e37f 100644
--- a/gcc/config/i386/i386-builtin-types.def
+++ b/gcc/config/i386/i386-builtin-types.def
@@ -1281,6 +1281,7 @@ DEF_FUNCTION_TYPE (V4SI, V4SI, V4SI, UHI)
 DEF_FUNCTION_TYPE (V8SI, V8SI, V8SI, UHI)
 
 # BF16 builtins
+DEF_FUNCTION_TYPE (FLOAT, BFLOAT16)
 DEF_FUNCTION_TYPE (V32BF, V16SF, V16SF)
 DEF_FUNCTION_TYPE (V32BF, V16SF, V16SF, V32BF, USI)
 DEF_FUNCTION_TYPE (V32BF, V16SF, V16SF, USI)
diff --git a/gcc/config/i386/i386-builtin.def b/gcc/config/i386/i386-builtin.def
index 5e0461acc00..d85b1753039 100644
--- a/gcc/config/i386/i386-builtin.def
+++ b/gcc/config/i386/i386-builtin.def
@@ -2838,6 +2838,8 @@ BDESC (0, OPTION_MASK_ISA2_AVX512BF16, CODE_FOR_avx512f_dpbf16ps_v8sf_maskz, "__
 BDESC (0, OPTION_MASK_ISA2_AVX512BF16, CODE_FOR_avx512f_dpbf16ps_v4sf, "__builtin_ia32_dpbf16ps_v4sf", IX86_BUILTIN_DPBF16PS_V4SF, UNKNOWN, (int) V4SF_FTYPE_V4SF_V8BF_V8BF)
 BDESC (0, OPTION_MASK_ISA2_AVX512BF16, CODE_FOR_avx512f_dpbf16ps_v4sf_mask, "__builtin_ia32_dpbf16ps_v4sf_mask", IX86_BUILTIN_DPBF16PS_V4SF_MASK, UNKNOWN, (int) V4SF_FTYPE_V4SF_V8BF_V8BF_UQI)
 BDESC (0, OPTION_MASK_ISA2_AVX512BF16, CODE_FOR_avx512f_dpbf16ps_v4sf_maskz, "__builtin_ia32_dpbf16ps_v4sf_maskz", IX86_BUILTIN_DPBF16PS_V4SF_MASKZ, UNKNOWN, (int) V4SF_FTYPE_V4SF_V8BF_V8BF_UQI)
+BDESC (OPTION_MASK_ISA_SSE2, 0, CODE_FOR_extendbfsf2_1, "__builtin_ia32_cvtbf2sf", IX86_BUILTIN_CVTBF2SF, UNKNOWN, (int) FLOAT_FTYPE_BFLOAT16)
+
 
 /* AVX512FP16.  */
 BDESC (OPTION_MASK_ISA_AVX512VL, OPTION_MASK_ISA2_AVX512FP16, CODE_FOR_addv8hf3_mask, "__builtin_ia32_addph128_mask", IX86_BUILTIN_ADDPH128_MASK, UNKNOWN, (int) V8HF_FTYPE_V8HF_V8HF_V8HF_UQI)
diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index 0373c3614a4..d26e7e41445 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -10423,6 +10423,7 @@ ix86_expand_args_builtin (const struct builtin_description *d,
       return ix86_expand_sse_ptest (d, exp, target);
     case FLOAT128_FTYPE_FLOAT128:
     case FLOAT_FTYPE_FLOAT:
+    case FLOAT_FTYPE_BFLOAT16:
     case INT_FTYPE_INT:
     case UINT_FTYPE_UINT:
     case UINT16_FTYPE_UINT16:
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 01faa911b77..62d70330c5c 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -130,6 +130,7 @@ (define_c_enum "unspec" [
   ;; For AVX/AVX512F support
   UNSPEC_SCALEF
   UNSPEC_PCMP
+  UNSPEC_CVTBFSF
 
   ;; Generic math support
   UNSPEC_IEEE_MIN	; not commutative
@@ -4961,6 +4962,31 @@ (define_insn "*extendhf<mode>2"
    (set_attr "prefix" "evex")
    (set_attr "mode" "<MODE>")])
 
+(define_expand "extendbfsf2"
+  [(set (match_operand:SF 0 "register_operand")
+	(unspec:SF
+	  [(match_operand:BF 1 "register_operand")]
+	 UNSPEC_CVTBFSF))]
+ "TARGET_SSE2 && !HONOR_NANS (BFmode) && !flag_signaling_nans")
+
+;; Don't use float_extend since psrlld doesn't raise
+;; exceptions and turn a sNaN into a qNaN.
+(define_insn "extendbfsf2_1"
+  [(set (match_operand:SF 0 "register_operand"   "=x,Yw")
+	(unspec:SF
+	  [(match_operand:BF 1 "register_operand" " 0,Yw")]
+	  UNSPEC_CVTBFSF))]
+ "TARGET_SSE2"
+ "@
+  pslld\t{$16, %0|%0, 16}
+  vpslld\t{$16, %1, %0|%0, %1, 16}"
+  [(set_attr "isa" "noavx,avx")
+   (set_attr "type" "sseishft")
+   (set_attr "length_immediate" "1")
+   (set_attr "prefix_data16" "1,*")
+   (set_attr "prefix" "orig,vex")
+   (set_attr "mode" "TI")
+   (set_attr "memory" "none")])
 
 (define_expand "extend<mode>xf2"
   [(set (match_operand:XF 0 "nonimmediate_operand")
@@ -5177,7 +5203,20 @@ (define_insn "*trunc<mode>hf2"
   [(set_attr "type" "ssecvt")
    (set_attr "prefix" "evex")
    (set_attr "mode" "HF")])
-\f
+
+(define_insn "truncsfbf2"
+  [(set (match_operand:BF 0 "register_operand" "=x, v")
+	(float_truncate:BF
+	  (match_operand:SF 1 "register_operand" "x,v")))]
+  "((TARGET_AVX512BF16 && TARGET_AVX512VL) || TARGET_AVXNECONVERT)
+   && !HONOR_NANS (BFmode) && flag_unsafe_math_optimizations
+   && !flag_signaling_nans"
+  "@
+  %{vex%} vcvtneps2bf16\t{%1, %0|%0, %1}
+  vcvtneps2bf16\t{%1, %0|%0, %1}"
+  [(set_attr "isa" "avxneconvert,avx512bf16vl")
+   (set_attr "prefix" "vex,evex")])
+
 ;; Signed conversion to DImode.
 
 (define_expand "fix_truncxfdi2"
diff --git a/gcc/testsuite/gcc.target/i386/avx512bf16-cvtsbh2ss-1.c b/gcc/testsuite/gcc.target/i386/avx512bf16-cvtsbh2ss-1.c
index 8e929e6f159..edf30b583b9 100644
--- a/gcc/testsuite/gcc.target/i386/avx512bf16-cvtsbh2ss-1.c
+++ b/gcc/testsuite/gcc.target/i386/avx512bf16-cvtsbh2ss-1.c
@@ -1,8 +1,7 @@
 /* { dg-do compile } */
 /* { dg-options "-mavx512bf16 -O2" } */
 /* { dg-additional-options "-fno-PIE -mfpmath=sse" { target ia32 } } */
-/* { dg-final { scan-assembler-times "sall\[ \\t\]+\[^\{\n\]*16" 1 } } */
-/* { dg-final { scan-assembler-times "movl" 1 } } */
+/* { dg-final { scan-assembler-times "pslld" 1 } } */
 
 #include <immintrin.h>
 
diff --git a/gcc/testsuite/gcc.target/i386/extendbfsf.c b/gcc/testsuite/gcc.target/i386/extendbfsf.c
new file mode 100644
index 00000000000..a38fa68bdc9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/extendbfsf.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-mavx512bf16 -mavx512vl -O2 -ffast-math" } */
+/* { dg-final { scan-assembler-times "pslld" 1 } } */
+/* { dg-final { scan-assembler-times "vcvtneps2bf16" 1 } } */
+
+float
+extendsfbf (__bf16 a)
+{
+  return a;
+}
+
+__bf16
+truncsfbf (float a)
+{
+  return a;
+}
-- 
2.27.0