LoongArch: Provide fmin/fmax RTL pattern

We already had smin/smax RTL pattern using fmin/fmax instruction.  But
for smin/smax, it's unspecified what will happen if either operand is
NaN.  So we would generate calls to libc fmin/fmax functions with
-fno-finite-math-only (the default for all optimization levels expect
-Ofast).

But, LoongArch fmin/fmax instruction is IEEE-754-2008 conformant so we
can also use the instruction for fmin/fmax pattern and avoid the library
function call.

gcc/ChangeLog:

	* config/loongarch/loongarch.md (fmax<mode>3): New RTL pattern.
	(fmin<mode>3): Likewise.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/fmax-fmin.c: New test.

gcc/config/loongarch/loongarch.md

@@ -1023,6 +1023,24 @@
   [(set_attr "type" "fmove")
    (set_attr "mode" "<MODE>")])
 
+(define_insn "fmax<mode>3"
+  [(set (match_operand:ANYF 0 "register_operand" "=f")
+	(smax:ANYF (match_operand:ANYF 1 "register_operand" "f")
+		   (match_operand:ANYF 2 "register_operand" "f")))]
+  ""
+  "fmax.<fmt>\t%0,%1,%2"
+  [(set_attr "type" "fmove")
+   (set_attr "mode" "<MODE>")])
+
+(define_insn "fmin<mode>3"
+  [(set (match_operand:ANYF 0 "register_operand" "=f")
+	(smin:ANYF (match_operand:ANYF 1 "register_operand" "f")
+		   (match_operand:ANYF 2 "register_operand" "f")))]
+  ""
+  "fmin.<fmt>\t%0,%1,%2"
+  [(set_attr "type" "fmove")
+   (set_attr "mode" "<MODE>")])
+
 (define_insn "smaxa<mode>3"
   [(set (match_operand:ANYF 0 "register_operand" "=f")
 	(if_then_else:ANYF

gcc/testsuite/gcc.target/loongarch/fmax-fmin.c

@@ -0,0 +1,30 @@
+/* { dg-do compile } */
+/* { dg-options "-mdouble-float -fno-finite-math-only" } */
+/* { dg-final { scan-assembler "fmin\\.s" } } */
+/* { dg-final { scan-assembler "fmin\\.d" } } */
+/* { dg-final { scan-assembler "fmax\\.s" } } */
+/* { dg-final { scan-assembler "fmax\\.d" } } */
+
+double
+_fmax(double a, double b)
+{
+  return __builtin_fmax(a, b);
+}
+
+float
+_fmaxf(float a, float b)
+{
+  return __builtin_fmaxf(a, b);
+}
+
+double
+_fmin(double a, double b)
+{
+  return __builtin_fmin(a, b);
+}
+
+float
+_fminf(float a, float b)
+{
+  return __builtin_fminf(a, b);
+}