all: Fix implicit floating point promotion.

Initially some of these were found building the unix coverage variant on
MacOS because that build uses clang and has -Wdouble-promotion enabled, and
clang performs more vigorous promotion checks than gcc.  Additionally the
codebase has been compiled with clang and msvc (the latter with warning
level 3), and with MICROPY_FLOAT_IMPL_FLOAT to find the rest of the
conversions.

Fixes are implemented either as explicit casts, or by using the correct
type, or by using one of the utility functions to handle floating point
casting; these have been moved from nativeglue.c to the public API.

6 files changed, 58 insertions, 41 deletions

diff --git a/py/binary.c b/py/binary.c
index b29438770..33515e880 100644
--- a/py/binary.c
+++ b/py/binary.c
@@ -176,7 +176,7 @@ mp_obj_t mp_binary_get_val_array(char typecode, void *p, size_t index) {
         #endif
         #if MICROPY_PY_BUILTINS_FLOAT
         case 'f':
-            return mp_obj_new_float(((float *)p)[index]);
+            return mp_obj_new_float_from_f(((float *)p)[index]);
         case 'd':
             return mp_obj_new_float(((double *)p)[index]);
         #endif
@@ -244,7 +244,7 @@ mp_obj_t mp_binary_get_val(char struct_type, char val_type, byte *p_base, byte *
         union { uint32_t i;
                 float f;
         } fpu = {val};
-        return mp_obj_new_float(fpu.f);
+        return mp_obj_new_float_from_f(fpu.f);
     } else if (val_type == 'd') {
         union { uint64_t i;
                 double f;
@@ -320,7 +320,7 @@ void mp_binary_set_val(char struct_type, char val_type, mp_obj_t val_in, byte *p
                     uint32_t i32[2];
                     double f;
             } fp_dp;
-            fp_dp.f = mp_obj_get_float(val_in);
+            fp_dp.f = mp_obj_get_float_to_d(val_in);
             if (BYTES_PER_WORD == 8) {
                 val = fp_dp.i64;
             } else {
@@ -362,7 +362,7 @@ void mp_binary_set_val_array(char typecode, void *p, size_t index, mp_obj_t val_
             ((float *)p)[index] = mp_obj_get_float(val_in);
             break;
         case 'd':
-            ((double *)p)[index] = mp_obj_get_float(val_in);
+            ((double *)p)[index] = mp_obj_get_float_to_d(val_in);
             break;
         #endif
         // Extension to CPython: array of objects
diff --git a/py/modcmath.c b/py/modcmath.c
index ce1f4746f..f1ce8fb5d 100644
--- a/py/modcmath.c
+++ b/py/modcmath.c
@@ -72,7 +72,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_cmath_exp_obj, mp_cmath_exp);
 STATIC mp_obj_t mp_cmath_log(mp_obj_t z_obj) {
     mp_float_t real, imag;
     mp_obj_get_complex(z_obj, &real, &imag);
-    return mp_obj_new_complex(0.5 * MICROPY_FLOAT_C_FUN(log)(real * real + imag * imag), MICROPY_FLOAT_C_FUN(atan2)(imag, real));
+    return mp_obj_new_complex(MICROPY_FLOAT_CONST(0.5) * MICROPY_FLOAT_C_FUN(log)(real * real + imag * imag), MICROPY_FLOAT_C_FUN(atan2)(imag, real));
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_cmath_log_obj, mp_cmath_log);
 
@@ -81,7 +81,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_cmath_log_obj, mp_cmath_log);
 STATIC mp_obj_t mp_cmath_log10(mp_obj_t z_obj) {
     mp_float_t real, imag;
     mp_obj_get_complex(z_obj, &real, &imag);
-    return mp_obj_new_complex(0.5 * MICROPY_FLOAT_C_FUN(log10)(real * real + imag * imag), 0.4342944819032518 * MICROPY_FLOAT_C_FUN(atan2)(imag, real));
+    return mp_obj_new_complex(MICROPY_FLOAT_CONST(0.5) * MICROPY_FLOAT_C_FUN(log10)(real * real + imag * imag), MICROPY_FLOAT_CONST(0.4342944819032518) * MICROPY_FLOAT_C_FUN(atan2)(imag, real));
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_cmath_log10_obj, mp_cmath_log10);
 #endif
@@ -90,8 +90,8 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_cmath_log10_obj, mp_cmath_log10);
 STATIC mp_obj_t mp_cmath_sqrt(mp_obj_t z_obj) {
     mp_float_t real, imag;
     mp_obj_get_complex(z_obj, &real, &imag);
-    mp_float_t sqrt_abs = MICROPY_FLOAT_C_FUN(pow)(real * real + imag * imag, 0.25);
-    mp_float_t theta = 0.5 * MICROPY_FLOAT_C_FUN(atan2)(imag, real);
+    mp_float_t sqrt_abs = MICROPY_FLOAT_C_FUN(pow)(real * real + imag * imag, MICROPY_FLOAT_CONST(0.25));
+    mp_float_t theta = MICROPY_FLOAT_CONST(0.5) * MICROPY_FLOAT_C_FUN(atan2)(imag, real);
     return mp_obj_new_complex(sqrt_abs * MICROPY_FLOAT_C_FUN(cos)(theta), sqrt_abs * MICROPY_FLOAT_C_FUN(sin)(theta));
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_cmath_sqrt_obj, mp_cmath_sqrt);
diff --git a/py/nativeglue.c b/py/nativeglue.c
index eebbe18bb..30e5b4006 100644
--- a/py/nativeglue.c
+++ b/py/nativeglue.c
@@ -227,25 +227,7 @@ STATIC bool mp_native_yield_from(mp_obj_t gen, mp_obj_t send_value, mp_obj_t *re
     return false;
 }
 
-#if MICROPY_PY_BUILTINS_FLOAT
-
-STATIC mp_obj_t mp_obj_new_float_from_f(float f) {
-    return mp_obj_new_float((mp_float_t)f);
-}
-
-STATIC mp_obj_t mp_obj_new_float_from_d(double d) {
-    return mp_obj_new_float((mp_float_t)d);
-}
-
-STATIC float mp_obj_get_float_to_f(mp_obj_t o) {
-    return (float)mp_obj_get_float(o);
-}
-
-STATIC double mp_obj_get_float_to_d(mp_obj_t o) {
-    return (double)mp_obj_get_float(o);
-}
-
-#else
+#if !MICROPY_PY_BUILTINS_FLOAT
 
 STATIC mp_obj_t mp_obj_new_float_from_f(float f) {
     (void)f;
diff --git a/py/obj.h b/py/obj.h
index b282c63db..d3abdab59 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -820,6 +820,39 @@ void mp_str_print_quoted(const mp_print_t *print, const byte *str_data, size_t s
 
 #if MICROPY_PY_BUILTINS_FLOAT
 // float
+#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
+static inline float mp_obj_get_float_to_f(mp_obj_t o) {
+    return mp_obj_get_float(o);
+}
+
+static inline double mp_obj_get_float_to_d(mp_obj_t o) {
+    return (double)mp_obj_get_float(o);
+}
+
+static inline mp_obj_t mp_obj_new_float_from_f(float o) {
+    return mp_obj_new_float(o);
+}
+
+static inline mp_obj_t mp_obj_new_float_from_d(double o) {
+    return mp_obj_new_float((mp_float_t)o);
+}
+#elif MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
+static inline float mp_obj_get_float_to_f(mp_obj_t o) {
+    return (float)mp_obj_get_float(o);
+}
+
+static inline double mp_obj_get_float_to_d(mp_obj_t o) {
+    return mp_obj_get_float(o);
+}
+
+static inline mp_obj_t mp_obj_new_float_from_f(float o) {
+    return mp_obj_new_float((mp_float_t)o);
+}
+
+static inline mp_obj_t mp_obj_new_float_from_d(double o) {
+    return mp_obj_new_float(o);
+}
+#endif
 #if MICROPY_FLOAT_HIGH_QUALITY_HASH
 mp_int_t mp_float_hash(mp_float_t val);
 #else
diff --git a/py/objfloat.c b/py/objfloat.c
index c7cf049fb..09b73c8cd 100644
--- a/py/objfloat.c
+++ b/py/objfloat.c
@@ -52,11 +52,13 @@ typedef struct _mp_obj_float_t {
     mp_float_t value;
 } mp_obj_float_t;
 
-const mp_obj_float_t mp_const_float_e_obj = {{&mp_type_float}, M_E};
-const mp_obj_float_t mp_const_float_pi_obj = {{&mp_type_float}, M_PI};
+const mp_obj_float_t mp_const_float_e_obj = {{&mp_type_float}, (mp_float_t)M_E};
+const mp_obj_float_t mp_const_float_pi_obj = {{&mp_type_float}, (mp_float_t)M_PI};
 
 #endif
 
+#define MICROPY_FLOAT_ZERO MICROPY_FLOAT_CONST(0.0)
+
 #if MICROPY_FLOAT_HIGH_QUALITY_HASH
 // must return actual integer value if it fits in mp_int_t
 mp_int_t mp_float_hash(mp_float_t src) {
@@ -208,24 +210,24 @@ STATIC void mp_obj_float_divmod(mp_float_t *x, mp_float_t *y) {
     mp_float_t div = (*x - mod) / *y;
 
     // Python specs require that mod has same sign as second operand
-    if (mod == 0.0) {
-        mod = MICROPY_FLOAT_C_FUN(copysign)(0.0, *y);
+    if (mod == MICROPY_FLOAT_ZERO) {
+        mod = MICROPY_FLOAT_C_FUN(copysign)(MICROPY_FLOAT_ZERO, *y);
     } else {
-        if ((mod < 0.0) != (*y < 0.0)) {
+        if ((mod < MICROPY_FLOAT_ZERO) != (*y < MICROPY_FLOAT_ZERO)) {
             mod += *y;
-            div -= 1.0;
+            div -= MICROPY_FLOAT_CONST(1.0);
         }
     }
 
     mp_float_t floordiv;
-    if (div == 0.0) {
+    if (div == MICROPY_FLOAT_ZERO) {
         // if division is zero, take the correct sign of zero
-        floordiv = MICROPY_FLOAT_C_FUN(copysign)(0.0, *x / *y);
+        floordiv = MICROPY_FLOAT_C_FUN(copysign)(MICROPY_FLOAT_ZERO, *x / *y);
     } else {
         // Python specs require that x == (x//y)*y + (x%y)
         floordiv = MICROPY_FLOAT_C_FUN(floor)(div);
-        if (div - floordiv > 0.5) {
-            floordiv += 1.0;
+        if (div - floordiv > MICROPY_FLOAT_CONST(0.5)) {
+            floordiv += MICROPY_FLOAT_CONST(1.0);
         }
     }
 
@@ -273,15 +275,15 @@ mp_obj_t mp_obj_float_binary_op(mp_binary_op_t op, mp_float_t lhs_val, mp_obj_t
             break;
         case MP_BINARY_OP_MODULO:
         case MP_BINARY_OP_INPLACE_MODULO:
-            if (rhs_val == 0) {
+            if (rhs_val == MICROPY_FLOAT_ZERO) {
                 goto zero_division_error;
             }
             lhs_val = MICROPY_FLOAT_C_FUN(fmod)(lhs_val, rhs_val);
             // Python specs require that mod has same sign as second operand
-            if (lhs_val == 0.0) {
+            if (lhs_val == MICROPY_FLOAT_ZERO) {
                 lhs_val = MICROPY_FLOAT_C_FUN(copysign)(0.0, rhs_val);
             } else {
-                if ((lhs_val < 0.0) != (rhs_val < 0.0)) {
+                if ((lhs_val < MICROPY_FLOAT_ZERO) != (rhs_val < MICROPY_FLOAT_ZERO)) {
                     lhs_val += rhs_val;
                 }
             }
diff --git a/py/parsenum.c b/py/parsenum.c
index 234248c9d..e665da7d8 100644
--- a/py/parsenum.c
+++ b/py/parsenum.c
@@ -220,7 +220,7 @@ mp_obj_t mp_parse_num_decimal(const char *str, size_t len, bool allow_imag, bool
         if (str + 2 < top && (str[1] | 0x20) == 'n' && (str[2] | 0x20) == 'f') {
             // inf
             str += 3;
-            dec_val = INFINITY;
+            dec_val = (mp_float_t)INFINITY;
             if (str + 4 < top && (str[0] | 0x20) == 'i' && (str[1] | 0x20) == 'n' && (str[2] | 0x20) == 'i' && (str[3] | 0x20) == 't' && (str[4] | 0x20) == 'y') {
                 // infinity
                 str += 5;