LoongArch: Improve TARGET_CAN_CHANGE_MODE_CLASS implementation

Support for conversion between scalar INT and scalar FP.

gcc/ChangeLog:

	* config/loongarch/loongarch.cc
	(loongarch_can_change_mode_class): Support for conversion
	between scalar INT and scalar FP.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/extendsidi2-combine.c: New test.
	* gcc.target/loongarch/spill-less.c: New test.

diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index 735753ad7e2d70a3879653ff5d66243368c87bea..ecc7e21f49c07217ba4b225635f864f6e850baf7 100644 (file)
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -7108,6 +7108,10 @@ static bool
 loongarch_can_change_mode_class (machine_mode from, machine_mode to,
                                 reg_class_t rclass)
 {
+  if ((INTEGRAL_MODE_P (from) && FLOAT_MODE_P (to))
+      || (INTEGRAL_MODE_P (to) && FLOAT_MODE_P (from)))
+    return true;
+
   /* Allow conversions between different LSX/LASX vector modes.  */
   if (LASX_SUPPORTED_MODE_P (from) && LASX_SUPPORTED_MODE_P (to))
     return true;

diff --git a/gcc/testsuite/gcc.target/loongarch/extendsidi2-combine.c b/gcc/testsuite/gcc.target/loongarch/extendsidi2-combine.c
new file mode 100644 (file)
index 0000000..0c3613c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/extendsidi2-combine.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { loongarch64*-*-* } } } */
+/* { dg-options "-O3 -fno-strict-aliasing" } */
+
+int
+test (double a)
+{
+  int z;
+
+  *((double *)&z) = a;
+  return z;
+}
+
+/* { dg-final { scan-assembler-not "slli\\.w" } } */

diff --git a/gcc/testsuite/gcc.target/loongarch/spill-less.c b/gcc/testsuite/gcc.target/loongarch/spill-less.c
new file mode 100644 (file)
index 0000000..77eb9b5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/spill-less.c
@@ -0,0 +1,14 @@
+/* { dg-do compile { target { loongarch64*-*-* } } } */
+/* { dg-options "-O3 -fno-strict-aliasing" } */
+
+double
+convert (long long in)
+{
+  double f;
+  *((long long *)&f) = in;
+  return f;
+}
+
+/* { dg-final { scan-assembler-not "st\\.d" } } */
+/* { dg-final { scan-assembler-not "fld\\.d" } } */
+/* { dg-final { scan-assembler "movgr2fr\\.d" } } */