arm: Split up MVE _Generic associations to prevent type clashes [PR107515]

With these previous patches:
https://gcc.gnu.org/pipermail/gcc-patches/2022-November/606586.html
https://gcc.gnu.org/pipermail/gcc-patches/2022-November/606587.html
we enabled the MVE overloaded _Generic associations to handle more
scalar types, however at PR 107515 we found a new regression that
wasn't detected in our testing:

With glibc's posix/types.h:
```
typedef signed int __int32_t;
...
typedef __int32_t int32_t;
```
We would get a `error: '_Generic' specifies two compatible types`
from `__ARM_mve_coerce3` because of `type: param`, when `type` is
`int` and `int32_t: param` both being the same under the hood.

The same did not happen with Newlib's header sys/_stdint.h:
```
typedef long int __int32_t;
...
typedef __int32_t int32_t ;
```
which worked fine, because it uses `long int`.

The same could feasibly happen in `__ARM_mve_coerce2` between
`__fp16` and `float16_t`.

The solution here is to break the _Generic down so that the similar
types don't appear at the same level, as is done in `__ARM_mve_typeid`

gcc/ChangeLog:
	PR target/96795
	PR target/107515
	* config/arm/arm_mve.h (__ARM_mve_coerce2): Split types.
	(__ARM_mve_coerce3): Likewise.

gcc/testsuite/ChangeLog:
	PR target/96795
	PR target/107515
	* gcc.target/arm/mve/intrinsics/mve_intrinsic_type_overloads-fp.c: New test.
	* gcc.target/arm/mve/intrinsics/mve_intrinsic_type_overloads-int.c: New test.

gcc/config/arm/arm_mve.h

@@ -35659,9 +35659,9 @@ extern void *__ARM_undef;
 #define __ARM_mve_coerce1(param, type) \
     _Generic(param, type: param, const type: param, default: *(type *)__ARM_undef)
 #define __ARM_mve_coerce2(param, type) \
-    _Generic(param, type: param, float16_t: param, float32_t: param, default: *(type *)__ARM_undef)
+    _Generic(param, type: param, __fp16: param, default: _Generic (param, _Float16: param, float16_t: param, float32_t: param, default: *(type *)__ARM_undef))
 #define __ARM_mve_coerce3(param, type) \
-    _Generic(param, type: param, int8_t: param, int16_t: param, int32_t: param, int64_t: param, uint8_t: param, uint16_t: param, uint32_t: param, uint64_t: param, default: *(type *)__ARM_undef)
+    _Generic(param, type: param, default: _Generic (param, int8_t: param, int16_t: param, int32_t: param, int64_t: param, uint8_t: param, uint16_t: param, uint32_t: param, uint64_t: param, default: *(type *)__ARM_undef))
 
 #if (__ARM_FEATURE_MVE & 2) /* MVE Floating point.  */
 

gcc/testsuite/gcc.target/arm/mve/intrinsics/mve_intrinsic_type_overloads-fp.c

@@ -0,0 +1,65 @@
+/* { dg-require-effective-target arm_v8_1m_mve_fp_ok } */
+/* { dg-add-options arm_v8_1m_mve_fp } */
+/* { dg-additional-options "-O2 -Wno-pedantic -Wno-long-long" } */
+#include "arm_mve.h"
+
+float f1;
+double f2;
+float16_t f3;
+float32_t f4;
+__fp16 f5;
+_Float16 f6;
+
+int i1;
+short i2;
+long i3;
+long long i4;
+int8_t i5;
+int16_t i6;
+int32_t i7;
+int64_t i8;
+
+const int ci1;
+const short ci2;
+const long ci3;
+const long long ci4;
+const int8_t ci5;
+const int16_t ci6;
+const int32_t ci7;
+const int64_t ci8;
+
+float16x8_t floatvec;
+int16x8_t intvec;
+
+void test(void)
+{
+    /* Test a few different supported ways of passing an int value.  The
+    intrinsic vmulq was chosen arbitrarily, but it is representative of
+    all intrinsics that take a non-const scalar value.  */
+    intvec = vmulq(intvec, 2);
+    intvec = vmulq(intvec, (int32_t) 2);
+    intvec = vmulq(intvec, (short) 2);
+    intvec = vmulq(intvec, i1);
+    intvec = vmulq(intvec, i2);
+    intvec = vmulq(intvec, i3);
+    intvec = vmulq(intvec, i4);
+    intvec = vmulq(intvec, i5);
+    intvec = vmulq(intvec, i6);
+    intvec = vmulq(intvec, i7);
+    intvec = vmulq(intvec, i8);
+
+    /* Test a few different supported ways of passing a float value.  */
+    floatvec = vmulq(floatvec, 0.5);
+    floatvec = vmulq(floatvec, 0.5f);
+    floatvec = vmulq(floatvec, (__fp16) 0.5);
+    floatvec = vmulq(floatvec, f1);
+    floatvec = vmulq(floatvec, f2);
+    floatvec = vmulq(floatvec, f3);
+    floatvec = vmulq(floatvec, f4);
+    floatvec = vmulq(floatvec, f5);
+    floatvec = vmulq(floatvec, f6);
+    floatvec = vmulq(floatvec, 0.15f16);
+    floatvec = vmulq(floatvec, (_Float16) 0.15);
+}
+
+/* { dg-final { scan-assembler-not "__ARM_undef" } } */

gcc/testsuite/gcc.target/arm/mve/intrinsics/mve_intrinsic_type_overloads-int.c

@@ -0,0 +1,45 @@
+/* { dg-require-effective-target arm_v8_1m_mve_ok } */
+/* { dg-add-options arm_v8_1m_mve } */
+/* { dg-additional-options "-O2 -Wno-pedantic -Wno-long-long" } */
+
+#include "arm_mve.h"
+
+int i1;
+short i2;
+long i3;
+long long i4;
+int8_t i5;
+int16_t i6;
+int32_t i7;
+int64_t i8;
+
+const int ci1;
+const short ci2;
+const long ci3;
+const long long ci4;
+const int8_t ci5;
+const int16_t ci6;
+const int32_t ci7;
+const int64_t ci8;
+
+int16x8_t intvec;
+
+void test(void)
+{
+    /* Test a few different supported ways of passing an int value.  The
+    intrinsic vmulq was chosen arbitrarily, but it is representative of
+    all intrinsics that take a non-const scalar value.  */
+    intvec = vmulq(intvec, 2);
+    intvec = vmulq(intvec, (int32_t) 2);
+    intvec = vmulq(intvec, (short) 2);
+    intvec = vmulq(intvec, i1);
+    intvec = vmulq(intvec, i2);
+    intvec = vmulq(intvec, i3);
+    intvec = vmulq(intvec, i4);
+    intvec = vmulq(intvec, i5);
+    intvec = vmulq(intvec, i6);
+    intvec = vmulq(intvec, i7);
+    intvec = vmulq(intvec, i8);
+}
+
+/* { dg-final { scan-assembler-not "__ARM_undef" } } */