LoongArch: Use standard pattern name for xvfrsqrt/vfrsqrt instructions.

Rename lasx_xvfrsqrt*/lsx_vfrsqrt* to rsqrt<mode>2 to align with standard
pattern name. Define function use_rsqrt_p to decide when to use rsqrt optab.

gcc/ChangeLog:

	* config/loongarch/lasx.md (lasx_xvfrsqrt_<flasxfmt>): Renamed to ..
	(rsqrt<mode>2): .. this.
	* config/loongarch/loongarch-builtins.cc
	(CODE_FOR_lsx_vfrsqrt_d): Redefine to standard pattern name.
	(CODE_FOR_lsx_vfrsqrt_s): Ditto.
	(CODE_FOR_lasx_xvfrsqrt_d): Ditto.
	(CODE_FOR_lasx_xvfrsqrt_s): Ditto.
	* config/loongarch/loongarch.cc (use_rsqrt_p): New function.
	(loongarch_optab_supported_p): Ditto.
	(TARGET_OPTAB_SUPPORTED_P): New hook.
	* config/loongarch/loongarch.md (*rsqrt<mode>a): Remove.
	(*rsqrt<mode>2): New insn pattern.
	(*rsqrt<mode>b): Remove.
	* config/loongarch/lsx.md (lsx_vfrsqrt_<flsxfmt>): Renamed to ..
	(rsqrt<mode>2): .. this.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/vector/lasx/lasx-rsqrt.c: New test.
	* gcc.target/loongarch/vector/lsx/lsx-rsqrt.c: New test.

7 files changed, 96 insertions, 23 deletions

diff --git a/gcc/config/loongarch/lasx.md b/gcc/config/loongarch/lasx.md
index b1416f6..3a4a1fe 100644
--- a/gcc/config/loongarch/lasx.md
+++ b/gcc/config/loongarch/lasx.md
@@ -1646,10 +1646,10 @@
   [(set_attr "type" "simd_fdiv")
    (set_attr "mode" "<MODE>")])
 
-(define_insn "lasx_xvfrsqrt_<flasxfmt>"
+(define_insn "rsqrt<mode>2"
   [(set (match_operand:FLASX 0 "register_operand" "=f")
-	(unspec:FLASX [(match_operand:FLASX 1 "register_operand" "f")]
-		      UNSPEC_LASX_XVFRSQRT))]
+    (unspec:FLASX [(match_operand:FLASX 1 "register_operand" "f")]
+		  UNSPEC_LASX_XVFRSQRT))]
   "ISA_HAS_LASX"
   "xvfrsqrt.<flasxfmt>\t%u0,%u1"
   [(set_attr "type" "simd_fdiv")
diff --git a/gcc/config/loongarch/loongarch-builtins.cc b/gcc/config/loongarch/loongarch-builtins.cc
index 507fc95..ba8686d 100644
--- a/gcc/config/loongarch/loongarch-builtins.cc
+++ b/gcc/config/loongarch/loongarch-builtins.cc
@@ -500,6 +500,8 @@ AVAIL_ALL (lasx_frecipe, ISA_HAS_LASX && TARGET_FRECIPE)
 #define CODE_FOR_lsx_vssrlrn_bu_h CODE_FOR_lsx_vssrlrn_u_bu_h
 #define CODE_FOR_lsx_vssrlrn_hu_w CODE_FOR_lsx_vssrlrn_u_hu_w
 #define CODE_FOR_lsx_vssrlrn_wu_d CODE_FOR_lsx_vssrlrn_u_wu_d
+#define CODE_FOR_lsx_vfrsqrt_d CODE_FOR_rsqrtv2df2
+#define CODE_FOR_lsx_vfrsqrt_s CODE_FOR_rsqrtv4sf2
 
 /* LoongArch ASX define CODE_FOR_lasx_mxxx */
 #define CODE_FOR_lasx_xvsadd_b CODE_FOR_ssaddv32qi3
@@ -776,6 +778,8 @@ AVAIL_ALL (lasx_frecipe, ISA_HAS_LASX && TARGET_FRECIPE)
 #define CODE_FOR_lasx_xvsat_hu CODE_FOR_lasx_xvsat_u_hu
 #define CODE_FOR_lasx_xvsat_wu CODE_FOR_lasx_xvsat_u_wu
 #define CODE_FOR_lasx_xvsat_du CODE_FOR_lasx_xvsat_u_du
+#define CODE_FOR_lasx_xvfrsqrt_d CODE_FOR_rsqrtv4df2
+#define CODE_FOR_lasx_xvfrsqrt_s CODE_FOR_rsqrtv8sf2
 
 static const struct loongarch_builtin_description loongarch_builtins[] = {
 #define LARCH_MOVFCSR2GR 0
diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index d9faf84..d5a920d 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -11492,6 +11492,30 @@ loongarch_builtin_support_vector_misalignment (machine_mode mode,
 						      is_packed);
 }
 
+static bool
+use_rsqrt_p (void)
+{
+  return (flag_finite_math_only
+	  && !flag_trapping_math
+	  && flag_unsafe_math_optimizations);
+}
+
+/* Implement the TARGET_OPTAB_SUPPORTED_P hook.  */
+
+static bool
+loongarch_optab_supported_p (int op, machine_mode, machine_mode,
+			     optimization_type opt_type)
+{
+  switch (op)
+    {
+    case rsqrt_optab:
+      return opt_type == OPTIMIZE_FOR_SPEED && use_rsqrt_p ();
+
+    default:
+      return true;
+    }
+}
+
 /* If -fverbose-asm, dump some info for debugging.  */
 static void
 loongarch_asm_code_end (void)
@@ -11630,6 +11654,9 @@ loongarch_asm_code_end (void)
 #undef TARGET_FUNCTION_ARG_BOUNDARY
 #define TARGET_FUNCTION_ARG_BOUNDARY loongarch_function_arg_boundary
 
+#undef TARGET_OPTAB_SUPPORTED_P
+#define TARGET_OPTAB_SUPPORTED_P loongarch_optab_supported_p
+
 #undef TARGET_VECTOR_MODE_SUPPORTED_P
 #define TARGET_VECTOR_MODE_SUPPORTED_P loongarch_vector_mode_supported_p
 
diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md
index b16dbd6..ba82ca7 100644
--- a/gcc/config/loongarch/loongarch.md
+++ b/gcc/config/loongarch/loongarch.md
@@ -60,6 +60,7 @@
   UNSPEC_TIE
 
   ;; RSQRT
+  UNSPEC_RSQRT
   UNSPEC_RSQRTE
 
   ;; RECIP
@@ -1134,25 +1135,14 @@
    (set_attr "mode" "<UNITMODE>")
    (set_attr "insn_count" "1")])
 
-(define_insn "*rsqrt<mode>a"
+(define_insn "*rsqrt<mode>2"
   [(set (match_operand:ANYF 0 "register_operand" "=f")
-	(div:ANYF (match_operand:ANYF 1 "const_1_operand" "")
-		  (sqrt:ANYF (match_operand:ANYF 2 "register_operand" "f"))))]
-  "flag_unsafe_math_optimizations"
-  "frsqrt.<fmt>\t%0,%2"
-  [(set_attr "type" "frsqrt")
-   (set_attr "mode" "<UNITMODE>")
-   (set_attr "insn_count" "1")])
-
-(define_insn "*rsqrt<mode>b"
-  [(set (match_operand:ANYF 0 "register_operand" "=f")
-	(sqrt:ANYF (div:ANYF (match_operand:ANYF 1 "const_1_operand" "")
-			     (match_operand:ANYF 2 "register_operand" "f"))))]
-  "flag_unsafe_math_optimizations"
-  "frsqrt.<fmt>\t%0,%2"
+    (unspec:ANYF [(match_operand:ANYF 1 "register_operand" "f")]
+	     UNSPEC_RSQRT))]
+  "TARGET_HARD_FLOAT"
+  "frsqrt.<fmt>\t%0,%1"
   [(set_attr "type" "frsqrt")
-   (set_attr "mode" "<UNITMODE>")
-   (set_attr "insn_count" "1")])
+   (set_attr "mode" "<UNITMODE>")])
 
 ;; Approximate Reciprocal Square Root Instructions.
 
diff --git a/gcc/config/loongarch/lsx.md b/gcc/config/loongarch/lsx.md
index 37bdc69..cb4a448 100644
--- a/gcc/config/loongarch/lsx.md
+++ b/gcc/config/loongarch/lsx.md
@@ -1559,10 +1559,10 @@
   [(set_attr "type" "simd_fdiv")
    (set_attr "mode" "<MODE>")])
 
-(define_insn "lsx_vfrsqrt_<flsxfmt>"
+(define_insn "rsqrt<mode>2"
   [(set (match_operand:FLSX 0 "register_operand" "=f")
-	(unspec:FLSX [(match_operand:FLSX 1 "register_operand" "f")]
-		     UNSPEC_LSX_VFRSQRT))]
+    (unspec:FLSX [(match_operand:FLSX 1 "register_operand" "f")]
+		 UNSPEC_LSX_VFRSQRT))]
   "ISA_HAS_LSX"
   "vfrsqrt.<flsxfmt>\t%w0,%w1"
   [(set_attr "type" "simd_fdiv")
diff --git a/gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-rsqrt.c b/gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-rsqrt.c
new file mode 100644
index 0000000..2431694
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-rsqrt.c
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mlasx -ffast-math" } */
+/* { dg-final { scan-assembler "xvfrsqrt.s" } } */
+/* { dg-final { scan-assembler "xvfrsqrt.d" } } */
+
+extern float sqrtf (float);
+
+float a[8], b[8];
+
+void
+foo1(void)
+{
+  for (int i = 0; i < 8; i++)
+    a[i] = 1 / sqrtf (b[i]);
+}
+
+extern double sqrt (double);
+
+double da[4], db[4];
+
+void
+foo2(void)
+{
+  for (int i = 0; i < 4; i++)
+    da[i] = 1 / sqrt (db[i]);
+}
diff --git a/gcc/testsuite/gcc.target/loongarch/vector/lsx/lsx-rsqrt.c b/gcc/testsuite/gcc.target/loongarch/vector/lsx/lsx-rsqrt.c
new file mode 100644
index 0000000..519cc47
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/vector/lsx/lsx-rsqrt.c
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mlsx -ffast-math" } */
+/* { dg-final { scan-assembler "vfrsqrt.s" } } */
+/* { dg-final { scan-assembler "vfrsqrt.d" } } */
+
+extern float sqrtf (float);
+
+float a[4], b[4];
+
+void
+foo1(void)
+{
+  for (int i = 0; i < 4; i++)
+    a[i] = 1 / sqrtf (b[i]);
+}
+
+extern double sqrt (double);
+
+double da[2], db[2];
+
+void
+foo2(void)
+{
+  for (int i = 0; i < 2; i++)
+    da[i] = 1 / sqrt (db[i]);
+}