[libclc] Fix int<->float conversion builtins (#126905)

While working on moving the conversion builtins to the CLC library in
25c0554 it was discovered that many weren't passing the OpenCL-CTS
tests.

As it happens, the clspv-specific code for conversion implementations
between integer and floating-point types was more correct. However:

* The clspv code was generating 'sat' conversions to floating-point
types, which are not legal
* The clspv code around rtn/rtz conversions needed tweaking as it wasn't
validating when sizeof(dst) > sizeof(src), e.g., int -> double.

With this commit, the CTS failures seen before have been resolved.

This also assumes that the new implementations are correct also for
clspv. If this is the case, then 'clc' and 'clspv' modes are mutually
exclusive and we can simplify the build process for conversions by not
building clc-clspv-convert.cl.

Author: frasercrmck

libclc/generic/lib/gen_convert.py

@@ -369,22 +369,13 @@ def generate_saturated_conversion(src, dst, size):
 
     elif src in float_types:
 
-        if clspv:
-            # Conversion from float to int
-            print(
-                f"""  {dstn} y = __clc_convert_{dstn}(x);
+        # Conversion from float to int
+        print(
+            f"""  {dstn} y = __clc_convert_{dstn}(x);
   y = __clc_select(y, ({dstn}){dst_min}, {bool_prefix}(x <= ({srcn}){dst_min}){bool_suffix});
   y = __clc_select(y, ({dstn}){dst_max}, {bool_prefix}(x >= ({srcn}){dst_max}){bool_suffix});
   return y;"""
-            )
-        else:
-            # Conversion from float to int
-            print(
-                f"""  {dstn} y = __clc_convert_{dstn}(x);
-  y = __clc_select(y, ({dstn}){dst_min}, {bool_prefix}(x < ({srcn}){dst_min}){bool_suffix});
-  y = __clc_select(y, ({dstn}){dst_max}, {bool_prefix}(x > ({srcn}){dst_max}){bool_suffix});
-  return y;"""
-            )
+        )
     else:
 
         # Integer to integer convesion with sizeof(src) == sizeof(dst)
@@ -494,7 +485,7 @@ def generate_float_conversion(src, dst, size, mode, sat):
         print(f"  return __clc_convert_{dstn}(x);")
     else:
         print(f"  {dstn} r = __clc_convert_{dstn}(x);")
-        if clspv:
+        if src in int_types:
             print(f"  {srcn} y = __clc_convert_{srcn}_sat(r);")
         else:
             print(f"  {srcn} y = __clc_convert_{srcn}(r);")
@@ -507,7 +498,7 @@ def generate_float_conversion(src, dst, size, mode, sat):
                 print(f"  {srcn} abs_x = __clc_fabs(x);")
                 print(f"  {srcn} abs_y = __clc_fabs(y);")
             print(f"  {booln} c = __clc_convert_{booln}(abs_y > abs_x);")
-            if clspv and sizeof_type[src] >= 4 and src in int_types:
+            if sizeof_type[src] >= sizeof_type[dst] and src in int_types:
                 print(f"  c = c || __clc_convert_{booln}(({srcn}){src_max} == x);")
             print(
                 f"  {dstn} sel = __clc_select(r, __clc_nextafter(r, __clc_sign(r) * ({dstn})-INFINITY), c);"
@@ -533,7 +524,7 @@ def generate_float_conversion(src, dst, size, mode, sat):
                 print("  return sel;")
         if mode == "_rtn":
             print(f"  {booln} c = __clc_convert_{booln}(y > x);")
-            if clspv and sizeof_type[src] >= 4 and src in int_types:
+            if sizeof_type[src] >= sizeof_type[dst] and src in int_types:
                 print(f"  c = c || __clc_convert_{booln}(({srcn}){src_max} == x);")
             print(
                 f"  {dstn} sel = __clc_select(r, __clc_nextafter(r, ({dstn})-INFINITY), c);"