From d50e743e0e534833aa5645234915c76e04307338 Mon Sep 17 00:00:00 2001
From: Graham Sanderson <graham.sanderson@raspberrypi.com>
Date: Tue, 12 Oct 2021 09:07:36 -0500
Subject: [PATCH] make type punning of floating point/int in float_math and
 double_math use union to avoid warnings (#600)

---
 src/rp2_common/pico_double/double_math.c | 77 ++++++++++++++----------
 src/rp2_common/pico_float/float_math.c   | 77 ++++++++++++++----------
 2 files changed, 90 insertions(+), 64 deletions(-)

diff --git a/src/rp2_common/pico_double/double_math.c b/src/rp2_common/pico_double/double_math.c
index c6db8c1..6c35ded 100644
--- a/src/rp2_common/pico_double/double_math.c
+++ b/src/rp2_common/pico_double/double_math.c
@@ -41,11 +41,25 @@ typedef int64_t i64;
 #define DUNPACK(x,e,m) e=((x)>>52)&0x7ff,m=((x)&0x000fffffffffffffULL)|0x0010000000000000ULL
 #define DUNPACKS(x,s,e,m) s=((x)>>63),DUNPACK((x),(e),(m))
 
-_Pragma("GCC diagnostic push")
-_Pragma("GCC diagnostic ignored \"-Wstrict-aliasing\"")
+typedef union {
+    double d;
+    ui64 ix;
+} double_ui64;
+
+static inline double ui642double(ui64 ix) {
+    double_ui64 tmp;
+    tmp.ix = ix;
+    return tmp.d;
+}
+
+static inline ui64 double2ui64(double d) {
+    double_ui64 tmp;
+    tmp.d = d;
+    return tmp.ix;
+}
 
 static inline bool disnan(double x) {
-    ui64 ix=*(ui64*)&x;
+    ui64 ix= double2ui64(x);
     // checks the top bit of the low 32 bit of the NAN, but it I think that is ok
     return ((uint32_t)(ix >> 31)) > 0xffe00000u;
 }
@@ -59,17 +73,17 @@ static inline bool disnan(double x) {
 #endif
 
 static inline int dgetsignexp(double x) {
-    ui64 ix=*(ui64*)&x;
+    ui64 ix=double2ui64(x);
     return (ix>>52)&0xfff;
 }
 
 static inline int dgetexp(double x) {
-    ui64 ix=*(ui64*)&x;
+    ui64 ix=double2ui64(x);
     return (ix>>52)&0x7ff;
 }
 
 static inline double dldexp(double x,int de) {
-    ui64 ix=*(ui64*)&x,iy;
+    ui64 ix=double2ui64(x),iy;
     int e;
     e=dgetexp(x);
     if(e==0||e==0x7ff) return x;
@@ -77,7 +91,7 @@ static inline double dldexp(double x,int de) {
     if(e<=0) iy=ix&0x8000000000000000ULL; // signed zero for underflow
     else if(e>=0x7ff) iy=(ix&0x8000000000000000ULL)|0x7ff0000000000000ULL; // signed infinity on overflow
     else iy=ix+((ui64)de<<52);
-    return *(double*)&iy;
+    return ui642double(iy);
 }
 
 double WRAPPER_FUNC(ldexp)(double x, int de) {
@@ -87,9 +101,9 @@ double WRAPPER_FUNC(ldexp)(double x, int de) {
 
 
 static inline double dcopysign(double x,double y) {
-    ui64 ix=*(ui64*)&x,iy=*(ui64*)&y;
+    ui64 ix=double2ui64(x),iy=double2ui64(y);
     ix=((ix&0x7fffffffffffffffULL)|(iy&0x8000000000000000ULL));
-    return *(double*)&ix;
+    return ui642double(ix);
 }
 
 double WRAPPER_FUNC(copysign)(double x, double y) {
@@ -104,7 +118,7 @@ static inline int dispinf(double x)  { return dgetsignexp(x)==0x7ff; }
 static inline int disminf(double x)  { return dgetsignexp(x)==0xfff; }
 
 static inline int disint(double x) {
-    ui64 ix=*(ui64*)&x,m;
+    ui64 ix=double2ui64(x),m;
     int e=dgetexp(x);
     if(e==0) return 1;       // 0 is an integer
     e-=0x3ff;                // remove exponent bias
@@ -117,7 +131,7 @@ static inline int disint(double x) {
 }
 
 static inline int disoddint(double x) {
-    ui64 ix=*(ui64*)&x,m;
+    ui64 ix=double2ui64(x),m;
     int e=dgetexp(x);
     e-=0x3ff;                // remove exponent bias
     if(e<0) return 0;        // |x|<1; 0 is not odd
@@ -130,24 +144,24 @@ static inline int disoddint(double x) {
 }
 
 static inline int disstrictneg(double x) {
-    ui64 ix=*(ui64*)&x;
+    ui64 ix=double2ui64(x);
     if(diszero(x)) return 0;
     return ix>>63;
 }
 
 static inline int disneg(double x) {
-    ui64 ix=*(ui64*)&x;
+    ui64 ix=double2ui64(x);
     return ix>>63;
 }
 
 static inline double dneg(double x) {
-    ui64 ix=*(ui64*)&x;
+    ui64 ix=double2ui64(x);
     ix^=0x8000000000000000ULL;
-    return *(double*)&ix;
+    return ui642double(ix);
 }
 
 static inline int dispo2(double x) {
-    ui64 ix=*(ui64*)&x;
+    ui64 ix=double2ui64(x);
     if(diszero(x)) return 0;
     if(disinf(x)) return 0;
     ix&=0x000fffffffffffffULL;
@@ -164,33 +178,33 @@ static inline double dnan_or(double x) {
 
 double WRAPPER_FUNC(trunc)(double x) {
     check_nan_d1(x);
-    ui64 ix=*(ui64*)&x,m;
+    ui64 ix=double2ui64(x),m;
     int e=dgetexp(x);
     e-=0x3ff;                // remove exponent bias
     if(e<0) {                // |x|<1
         ix&=0x8000000000000000ULL;
-        return *(double*)&ix;
+        return ui642double(ix);
     }
     e=52-e;                  // bit position in mantissa with significance 1
     if(e<=0) return x;       // |x| large, so must be an integer
     m=(1ULL<<e)-1;           // mask for bits of significance <1
     ix&=~m;
-    return *(double*)&ix;
+    return ui642double(ix);
 }
 
 double WRAPPER_FUNC(round)(double x) {
     check_nan_d1(x);
-    ui64 ix=*(ui64*)&x,m;
+    ui64 ix=double2ui64(x),m;
     int e=dgetexp(x);
     e-=0x3ff;                // remove exponent bias
     if(e<-1) {               // |x|<0.5
         ix&=0x8000000000000000ULL;
-        return *(double*)&ix;
+        return ui642double(ix);
     }
     if(e==-1) {              // 0.5<=|x|<1
         ix&=0x8000000000000000ULL;
         ix|=0x3ff0000000000000ULL;        // ±1
-        return *(double*)&ix;
+        return ui642double(ix);
     }
     e=52-e;                  // bit position in mantissa with significance 1, <=52
     if(e<=0) return x;       // |x| large, so must be an integer
@@ -198,16 +212,16 @@ double WRAPPER_FUNC(round)(double x) {
     ix+=m;
     m=m+m-1;                 // mask for bits of significance <1
     ix&=~m;
-    return *(double*)&ix;
+    return ui642double(ix);
 }
 
 double WRAPPER_FUNC(floor)(double x) {
     check_nan_d1(x);
-    ui64 ix=*(ui64*)&x,m;
+    ui64 ix=double2ui64(x),m;
     int e=dgetexp(x);
     if(e==0) {               // x==0
         ix&=0x8000000000000000ULL;
-        return *(double*)&ix;
+        return ui642double(ix);
     }
     e-=0x3ff;                // remove exponent bias
     if(e<0) {                // |x|<1, not zero
@@ -219,16 +233,16 @@ double WRAPPER_FUNC(floor)(double x) {
     m=(1ULL<<e)-1;           // mask for bit of significance <1
     if(disneg(x)) ix+=m;     // add 1-ε to magnitude if negative
     ix&=~m;                  // truncate
-    return *(double*)&ix;
+    return ui642double(ix);
 }
 
 double WRAPPER_FUNC(ceil)(double x) {
     check_nan_d1(x);
-    ui64 ix=*(ui64*)&x,m;
+    ui64 ix=double2ui64(x),m;
     int e=dgetexp(x);
     if(e==0) {               // x==0
         ix&=0x8000000000000000ULL;
-        return *(double*)&ix;
+        return ui642double(ix);
     }
     e-=0x3ff;                 // remove exponent bias
     if(e<0) {                // |x|<1, not zero
@@ -240,7 +254,7 @@ double WRAPPER_FUNC(ceil)(double x) {
     m=(1ULL<<e)-1;           // mask for bit of significance <1
     if(!disneg(x)) ix+=m;    // add 1-ε to magnitude if positive
     ix&=~m;                  // truncate
-    return *(double*)&ix;
+    return ui642double(ix);
 }
 
 double WRAPPER_FUNC(asin)(double x) {
@@ -549,7 +563,7 @@ static i64 drem_0(i64 mx,i64 my,int e,int*pquo) {
 
 double WRAPPER_FUNC(fmod)(double x,double y) {
     check_nan_d2(x, y);
-    ui64 ix=*(ui64*)&x,iy=*(ui64*)&y;
+    ui64 ix=double2ui64(x),iy=double2ui64(y);
     int sx,ex,ey;
     i64 mx,my;
     DUNPACKS(ix,sx,ex,mx);
@@ -568,7 +582,7 @@ double WRAPPER_FUNC(fmod)(double x,double y) {
 
 double WRAPPER_FUNC(remquo)(double x,double y,int*quo) {
     check_nan_d2(x, y);
-    ui64 ix=*(ui64*)&x,iy=*(ui64*)&y;
+    ui64 ix=double2ui64(x),iy=double2ui64(y);
     int sx,sy,ex,ey,q;
     i64 mx,my;
     DUNPACKS(ix,sx,ex,mx);
@@ -609,5 +623,4 @@ double WRAPPER_FUNC(drem)(double x,double y) { check_nan_d2(x, y); return remquo
 
 double WRAPPER_FUNC(remainder)(double x,double y) { check_nan_d2(x, y); return remquo(x,y,0); }
 
-_Pragma("GCC diagnostic pop") // strict-aliasing
 _Pragma("GCC diagnostic pop") // conversion
\ No newline at end of file
diff --git a/src/rp2_common/pico_float/float_math.c b/src/rp2_common/pico_float/float_math.c
index bc7fa9a..a48a2d7 100644
--- a/src/rp2_common/pico_float/float_math.c
+++ b/src/rp2_common/pico_float/float_math.c
@@ -39,11 +39,25 @@ typedef int32_t i32;
 #define FUNPACK(x,e,m) e=((x)>>23)&0xff,m=((x)&0x007fffff)|0x00800000
 #define FUNPACKS(x,s,e,m) s=((x)>>31),FUNPACK((x),(e),(m))
 
-_Pragma("GCC diagnostic push")
-_Pragma("GCC diagnostic ignored \"-Wstrict-aliasing\"")
+typedef union {
+    float f;
+    ui32 ix;
+} float_ui32;
+
+static inline float ui322float(ui32 ix) {
+    float_ui32 tmp;
+    tmp.ix = ix;
+    return tmp.f;
+}
+
+static inline ui32 float2ui32(float f) {
+    float_ui32 tmp;
+    tmp.f = f;
+    return tmp.ix;
+}
 
 static inline bool fisnan(float x) {
-    ui32 ix=*(ui32*)&x;
+    ui32 ix=float2ui32(x);
     return ix * 2 > 0xff000000u;
 }
 
@@ -56,17 +70,17 @@ static inline bool fisnan(float x) {
 #endif
 
 static inline int fgetsignexp(float x) {
-    ui32 ix=*(ui32*)&x;
+    ui32 ix=float2ui32(x);
     return (ix>>23)&0x1ff;
 }
 
 static inline int fgetexp(float x) {
-    ui32 ix=*(ui32*)&x;
+    ui32 ix=float2ui32(x);
     return (ix>>23)&0xff;
 }
 
 static inline float fldexp(float x,int de) {
-    ui32 ix=*(ui32*)&x,iy;
+    ui32 ix=float2ui32(x),iy;
     int e;
     e=fgetexp(x);
     if(e==0||e==0xff) return x;
@@ -74,7 +88,7 @@ static inline float fldexp(float x,int de) {
     if(e<=0) iy=ix&0x80000000; // signed zero for underflow
     else if(e>=0xff) iy=(ix&0x80000000)|0x7f800000ULL; // signed infinity on overflow
     else iy=ix+((ui32)de<<23);
-    return *(float*)&iy;
+    return ui322float(iy);
 }
 
 float WRAPPER_FUNC(ldexpf)(float x, int de) {
@@ -83,9 +97,9 @@ float WRAPPER_FUNC(ldexpf)(float x, int de) {
 }
 
 static inline float fcopysign(float x,float y) {
-    ui32 ix=*(ui32*)&x,iy=*(ui32*)&y;
+    ui32 ix=float2ui32(x),iy=float2ui32(y);
     ix=((ix&0x7fffffff)|(iy&0x80000000));
-    return *(float*)&ix;
+    return ui322float(ix);
 }
 
 float WRAPPER_FUNC(copysignf)(float x, float y) {
@@ -101,7 +115,7 @@ static inline int fispinf(float x)  { return fgetsignexp(x)==0xff; }
 static inline int fisminf(float x)  { return fgetsignexp(x)==0x1ff; }
 
 static inline int fisint(float x) {
-    ui32 ix=*(ui32*)&x,m;
+    ui32 ix=float2ui32(x),m;
     int e=fgetexp(x);
     if(e==0) return 1;       // 0 is an integer
     e-=0x7f;                 // remove exponent bias
@@ -114,7 +128,7 @@ static inline int fisint(float x) {
 }
 
 static inline int fisoddint(float x) {
-    ui32 ix=*(ui32*)&x,m;
+    ui32 ix=float2ui32(x),m;
     int e=fgetexp(x);
     e-=0x7f;                 // remove exponent bias
     if(e<0) return 0;        // |x|<1; 0 is not odd
@@ -127,24 +141,24 @@ static inline int fisoddint(float x) {
 }
 
 static inline int fisstrictneg(float x) {
-    ui32 ix=*(ui32*)&x;
+    ui32 ix=float2ui32(x);
     if(fiszero(x)) return 0;
     return ix>>31;
 }
 
 static inline int fisneg(float x) {
-    ui32 ix=*(ui32*)&x;
+    ui32 ix=float2ui32(x);
     return ix>>31;
 }
 
 static inline float fneg(float x) {
-    ui32 ix=*(ui32*)&x;
+    ui32 ix=float2ui32(x);
     ix^=0x80000000;
-    return *(float*)&ix;
+    return ui322float(ix);
 }
 
 static inline int fispo2(float x) {
-    ui32 ix=*(ui32*)&x;
+    ui32 ix=float2ui32(x);
     if(fiszero(x)) return 0;
     if(fisinf(x)) return 0;
     ix&=0x007fffff;
@@ -161,33 +175,33 @@ static inline float fnan_or(float x) {
 
 float WRAPPER_FUNC(truncf)(float x) {
     check_nan_f1(x);
-    ui32 ix=*(ui32*)&x,m;
+    ui32 ix=float2ui32(x),m;
     int e=fgetexp(x);
     e-=0x7f;                 // remove exponent bias
     if(e<0) {                // |x|<1
         ix&=0x80000000;
-        return *(float*)&ix;
+        return ui322float(ix);
     }
     e=23-e;                  // bit position in mantissa with significance 1
     if(e<=0) return x;       // |x| large, so must be an integer
     m=(1<<e)-1;              // mask for bits of significance <1
     ix&=~m;
-    return *(float*)&ix;
+    return ui322float(ix);
 }
 
 float WRAPPER_FUNC(roundf)(float x) {
     check_nan_f1(x);
-    ui32 ix=*(ui32*)&x,m;
+    ui32 ix=float2ui32(x),m;
     int e=fgetexp(x);
     e-=0x7f;                 // remove exponent bias
     if(e<-1) {               // |x|<0.5
         ix&=0x80000000;
-        return *(float*)&ix;
+        return ui322float(ix);
     }
     if(e==-1) {              // 0.5<=|x|<1
         ix&=0x80000000;
         ix|=0x3f800000;        // ±1
-        return *(float*)&ix;
+        return ui322float(ix);
     }
     e=23-e;                  // bit position in mantissa with significance 1, <=23
     if(e<=0) return x;       // |x| large, so must be an integer
@@ -195,16 +209,16 @@ float WRAPPER_FUNC(roundf)(float x) {
     ix+=m;
     m=m+m-1;                 // mask for bits of significance <1
     ix&=~m;
-    return *(float*)&ix;
+    return ui322float(ix);
 }
 
 float WRAPPER_FUNC(floorf)(float x) {
     check_nan_f1(x);
-    ui32 ix=*(ui32*)&x,m;
+    ui32 ix=float2ui32(x),m;
     int e=fgetexp(x);
     if(e==0) {       // x==0
         ix&=0x80000000;
-        return *(float*)&ix;
+        return ui322float(ix);
     }
     e-=0x7f;                 // remove exponent bias
     if(e<0) {                // |x|<1, not zero
@@ -216,16 +230,16 @@ float WRAPPER_FUNC(floorf)(float x) {
     m=(1<<e)-1;              // mask for bit of significance <1
     if(fisneg(x)) ix+=m;     // add 1-ε to magnitude if negative
     ix&=~m;                  // truncate
-    return *(float*)&ix;
+    return ui322float(ix);
 }
 
 float WRAPPER_FUNC(ceilf)(float x) {
     check_nan_f1(x);
-    ui32 ix=*(ui32*)&x,m;
+    ui32 ix=float2ui32(x),m;
     int e=fgetexp(x);
     if(e==0) {       // x==0
         ix&=0x80000000;
-        return *(float*)&ix;
+        return ui322float(ix);
     }
     e-=0x7f;                 // remove exponent bias
     if(e<0) {                // |x|<1, not zero
@@ -237,7 +251,7 @@ float WRAPPER_FUNC(ceilf)(float x) {
     m=(1<<e)-1;              // mask for bit of significance <1
     if(!fisneg(x)) ix+=m;    // add 1-ε to magnitude if positive
     ix&=~m;                  // truncate
-    return *(float*)&ix;
+    return ui322float(ix);
 }
 
 float WRAPPER_FUNC(asinf)(float x) {
@@ -505,7 +519,7 @@ static i32 frem_0(i32 mx,i32 my,int e,int*pquo) {
 
 float WRAPPER_FUNC(fmodf)(float x,float y) {
     check_nan_f2(x,y);
-    ui32 ix=*(ui32*)&x,iy=*(ui32*)&y;
+    ui32 ix=float2ui32(x),iy=float2ui32(y);
     int sx,ex,ey;
     i32 mx,my;
     FUNPACKS(ix,sx,ex,mx);
@@ -526,7 +540,7 @@ float WRAPPER_FUNC(fmodf)(float x,float y) {
 
 float WRAPPER_FUNC(remquof)(float x,float y,int*quo) {
     check_nan_f2(x,y);
-    ui32 ix=*(ui32*)&x,iy=*(ui32*)&y;
+    ui32 ix=float2ui32(x),iy=float2ui32(y);
     int sx,sy,ex,ey,q;
     i32 mx,my;
     FUNPACKS(ix,sx,ex,mx);
@@ -567,5 +581,4 @@ float WRAPPER_FUNC(dremf)(float x,float y) { check_nan_f2(x,y); return remquof(x
 
 float WRAPPER_FUNC(remainderf)(float x,float y) { check_nan_f2(x,y); return remquof(x,y,0); }
 
-_Pragma("GCC diagnostic pop") // strict-aliasing
 _Pragma("GCC diagnostic pop") // conversion
\ No newline at end of file