Some fixes for undefined behaviour (edited by TU)

This is extracted from the commit 29854a5 to synchronize and make it
easy to merge the "diagrams" branch in future. Most of them are for
removing "left shift of negative value" (e.g., -100 << 4). Note that,
on x86-64, both "a <<= 1" and "a *= 2" are naturally optimized as
"a = a + a" (at least with gcc 7.2, clang 5.0.0 and icc 17).

sources/argument.c

@@ -528,7 +528,7 @@ ScaledVariety:;
 					r4 = AddRHS(AT.ebufnum,1);
 					while ( (r4+j+12) > CC->Top ) r4 = DoubleCbuffer(AT.ebufnum,r4,3);
 					*r4++ = j+1;
-					i = (j-1)>>1;
+					i = (j-1)/2;  /* was (j-1)*2  ????? 17-oct-2017 */
 					for ( k = 0; k < i; k++ ) *r4++ = r3[i+k];
 					for ( k = 0; k < i; k++ ) *r4++ = r3[k];
 					if ( ( type == TYPENORM3 ) || ( type == TYPENORM4 ) ) *r4++ = j*sign;

sources/compcomm.c

@@ -4229,7 +4229,7 @@ int CoIf(UBYTE *inp)
 				}
 			}
 			u[1] = WORDDIF(w,u);
-			u[2] = (u[1] - 3)>>1;
+			u[2] = (u[1] - 3)/2;
 			if ( level ) u[2] = -u[2];
 			gotexp = 1;
 		}

sources/declare.h

@@ -41,12 +41,15 @@
 #define MiN(x,y) ((x) < (y) ? (x): (y))
 #define ABS(x) ( (x) < 0 ? -(x): (x) )
 #define SGN(x) ( (x) > 0 ? 1 : (x) < 0 ? -1 : 0 )
-#define REDLENG(x) ((((x)<0)?((x)+1):((x)-1))>>1)
-#define INCLENG(x) (((x)<0)?(((x)<<1)-1):(((x)<<1)+1))
+#define REDLENG(x) ((((x)<0)?((x)+1):((x)-1))/2)
+#define INCLENG(x) (((x)<0)?(((x)*2)-1):(((x)*2)+1))
 #define GETCOEF(x,y) x += *x;y = x[-1];x -= ABS(y);y=REDLENG(y)
 #define GETSTOP(x,y) y=x+(*x)-1;y -= ABS(*y)-1
 #define StuffAdd(x,y)  (((x)<0?-1:1)*(y)+((y)<0?-1:1)*(x))
 
+#define EXCHN(t1,t2,n) { WORD a,i; for(i=0;i<n;i++){a=t1[i];t1[i]=t2[i];t2[i]=a;} }
+#define EXCH(x,y) { WORD a = (x); (x) = (y); (y) = a; }
+
 #define TOKENTOLINE(x,y) if ( AC.OutputSpaces == NOSPACEFORMAT ) { \
 		TokenToLine((UBYTE *)(y)); } else { TokenToLine((UBYTE *)(x)); }
 

sources/minos.h

@@ -140,8 +140,8 @@ typedef struct compile {
  */
 #define TODISK 0
 #define FROMDISK 1
-#define MCLEANFLAG -2L
-#define DIRTYFLAG 1
+#define MDIRTYFLAG 1
+#define MCLEANFLAG (~MDIRTYFLAG)
 #define INANDOUT 0
 #define INPUTONLY 1
 #define OUTPUTONLY 2

sources/normal.c

@@ -714,7 +714,7 @@ NextSymbol:;
 								k = -t[1]-NMIN4SHIFT;
 								k = ExtraSymbol(k,1,nsym,ppsym,&ncoef);
 								nsym += k;
-								ppsym += (k << 1);
+								ppsym += (k * 2);
 							}
 							else if ( t[1] == 0 ) goto NormZero;
 							else {
@@ -1742,7 +1742,7 @@ gcdcalc:					if ( GcdLong(BHEAD (UWORD *)num1,size1,(UWORD *)num2,size2
 							for ( iii = 2; iii < t1[1]; iii += 2 ) {
 								change = ExtraSymbol(t1[iii],t1[iii+1],nsym,ppsym,&ncoef);
 								nsym += change;
-								ppsym += change << 1;
+								ppsym += change * 2;
 							}
 						}
 						t1 = gcd + *gcd;
@@ -2571,7 +2571,7 @@ TryAgain:;
 				t += FUNHEAD+1;
 				change = ExtraSymbol(*t,-1,nsym,ppsym,&ncoef);
 				nsym += change;
-				ppsym += change << 1;
+				ppsym += change * 2;
 				goto DropDen;
 			}
 			else if ( t[FUNHEAD] == -SNUMBER ) {
@@ -2621,7 +2621,7 @@ TryAgain:;
 								WORD change;
 								change = ExtraSymbol(*t,-t[1],nsym,ppsym,&ncoef);
 								nsym += change;
-								ppsym += change << 1;
+								ppsym += change * 2;
 								t += 2;
 							}
 						}
@@ -2694,7 +2694,7 @@ WithFix:				shortnum = k;
 						WORD change;
 						change = ExtraSymbol((WORD)(-k),(WORD)1,nsym,ppsym,&ncoef);
 						nsym += change;
-						ppsym += change << 1;
+						ppsym += change * 2;
 	   				}
 					t[1] = pdel[ndel-1];
 					t[0] = pdel[ndel-2];
@@ -5103,9 +5103,6 @@ int TestFunFlag(PHEAD WORD *tfun)
   	#[ BracketNormalize :
 */
 
-#define EXCHN(t1,t2,n) { WORD a,i; for(i=0;i<n;i++){x=t1[i];t1[i]=t2[i];t2[i]=a;}
-#define EXCH(x,y) { WORD a = (x); (x) = (y); (y) = a; }
-
 WORD BracketNormalize(PHEAD WORD *term)
 {
 	WORD *stop = term+*term-3, *t, *tt, *tstart, *r;

sources/opera.c

@@ -136,7 +136,7 @@ WORD EpfFind(PHEAD WORD *term, WORD *params)
 	mstop = c2;
 	fac = t[1] - FUNHEAD;
 	m = AT.TMout;
-	*m++ = 3 + (min<<1);		/* The full length */
+	*m++ = 3 + (min*2);		/* The full length */
 	*m++ = CONTRACT;
 	if ( number < 0 ) *m++ = 1;
 	else *m++ = 0;
@@ -183,9 +183,9 @@ WORD EpfFind(PHEAD WORD *term, WORD *params)
 		MUNLOCK(ErrorMessageLock);
 		SETERROR(-1)
 	}
-	tstop += (ABS(ncoef))<<1;
+	tstop += (ABS(ncoef))*2;
 	if ( sgn < 0 ) ncoef = -ncoef;
-	ncoef <<= 1;
+	ncoef *= 2;
 	*tstop++ = (ncoef<0)?(ncoef-1):(ncoef+1);
 	*term = WORDDIF(tstop,term);
 	return(1);
@@ -284,7 +284,7 @@ WORD EpfGen(WORD number, WORD *inlist, WORD *kron, WORD *perm, WORD sgn)
 	WORD i, *in2, k, a;
 	if ( !sgn ) {
 		in2 = inlist + number;
-		number <<= 1;
+		number *= 2;
 		for ( i = 1; i < number; i += 2 ) {
 			*perm++ = i;
 			*perm++ = i;
@@ -294,7 +294,7 @@ WORD EpfGen(WORD number, WORD *inlist, WORD *kron, WORD *perm, WORD sgn)
 		if ( number <= 0 ) return(0);
 		else return(1);
 	}
-	number <<= 1;
+	number *= 2;
 	i = number - 1;
 	while ( ( i -= 2 ) >= 0 ) {
 		if ( ( k = perm[i] ) != i ) {
@@ -433,7 +433,7 @@ WORD Trace4no(WORD number, WORD *kron, TRACES *t)
 		t->sgn = 1;
 		{
 			WORD nhalf = number >> 1;
-			WORD ndouble = number << 1;
+			WORD ndouble = number * 2;
 			p = t->eers;
 			t->eers = p;	p += nhalf;
 			t->mepf = p;	p += nhalf;
@@ -727,7 +727,7 @@ WORD Trace4(PHEAD WORD *term, WORD *params, WORD num, WORD level)
 	}
 	t->inlist = AT.WorkPointer;
 	t->accup = t->accu = t->inlist + number;
-	t->perm = t->accu + (number<<1);
+	t->perm = t->accu + (number*2);
 	t->eers = t->perm + number;
 	if ( ( AT.WorkPointer += 19 * number ) >= AT.WorkTop ) {
 		MLOCK(ErrorMessageLock);

sources/parallel.c

@@ -810,7 +810,7 @@ static int PF_GetLoser(NODE *n)
 /*
 					keep the left term and get the loser of right subtree
 */
-				newnlen <<= 1;
+				newnlen *= 2;
 				newclen = ( newnlen > 0 ) ? ( newnlen + 1 ) : ( newnlen - 1 );
 				if ( newnlen < 0 ) newnlen = -newnlen;
 				PF_newclen[n->lloser] = newclen;

sources/proces.c

@@ -2580,7 +2580,7 @@ ComAct:		if ( t < u ) do { *m++ = *t++; } while ( t < u );
 				if ( MulRat(BHEAD (UWORD *)u,REDLENG(l1),(UWORD *)r,REDLENG(l2),
 				(UWORD *)m,&l1) ) goto InsCall;
 				l2 = l1;
-				l2 <<= 1;
+				l2 *= 2;
 				if ( l2 < 0 ) {
 					m -= l2;
 					*m++ = l2-1;
@@ -2804,7 +2804,7 @@ WORD *PasteTerm(PHEAD WORD number, WORD *accum, WORD *position, WORD times, WORD
 			return(0);
 		}
 		x = l1;
-		x <<= 1;
+		x *= 2;
 		if ( x < 0 ) { accum -= x; *accum++ = x - 1; }
 		else		 { accum += x; *accum++ = x + 1; }
 		*u = WORDDIF(accum,u);
@@ -2976,7 +2976,7 @@ Nextr:;
 			}
 
 			i = ABS(l2);
-			i <<= 1;
+			i *= 2;
 			i++;
 			l2 = ( l2 >= 0 ) ? i: -i;
 			r = coef;
@@ -4897,7 +4897,7 @@ WORD PrepPoly(PHEAD WORD *term,WORD par)
 				while ( t < vv ) *m++ = *t++;
 				if ( MulRat(BHEAD (UWORD *)vv,ncoef,(UWORD *)tstop,jcoef,
 					(UWORD *)m,&ncoef) ) Terminate(-1);
-				ncoef <<= 1;
+				ncoef *= 2;
 				m += ABS(ncoef);
 				if ( ncoef < 0 ) ncoef--;
 				else ncoef++;

sources/ratio.c

@@ -489,7 +489,7 @@ WORD Glue(PHEAD WORD *term1, WORD *term2, WORD *sub, WORD insert)
 		TermFree(coef,"Glue");
 		SETERROR(-1)
 	}
-	i = (ABS(nc3))<<1;
+	i = (ABS(nc3))*2;
 	t += i++;
 	*t++ = (nc3 >= 0)?i:-i;
 	*term1 = WORDDIF(t,term1);

sources/reken.c

@@ -216,15 +216,15 @@ WORD AddRat(PHEAD UWORD *a, WORD na, UWORD *b, WORD nb, UWORD *c, WORD *nc)
 		WORD i;
 		*nc = nb;
 		if ( nb < 0 ) nb = -nb;
-		nb <<= 1;
+		nb *= 2;
 		for ( i = 0; i < nb; i++ ) *c++ = *b++;
 		return(0);
 	}
 	else if ( !nb ) {
 		WORD i;
 		*nc = na;
 		if ( na < 0 ) na = -na;
-		na <<= 1;
+		na *= 2;
 		for ( i = 0; i < na; i++ ) *c++ = *a++;
 		return(0);
 	}
@@ -382,27 +382,27 @@ WORD MulRat(PHEAD UWORD *a, WORD na, UWORD *b, WORD nb, UWORD *c, WORD *nc)
 	if ( *b == 1 && b[1] == 1 ) {
 		if ( nb == 1 ) {
 			*nc = na;
-			i = ABS(na); i <<= 1;
+			i = ABS(na); i *= 2;
 			while ( --i >= 0 ) *c++ = *a++;
 			return(0);
 		}
 		else if ( nb == -1 ) {
 			*nc = - na;
-			i = ABS(na); i <<= 1;
+			i = ABS(na); i *= 2;
 			while ( --i >= 0 ) *c++ = *a++;
 			return(0);
 		}
 	}
 	if ( *a == 1 && a[1] == 1 ) {
 		if ( na == 1 ) {
 			*nc = nb;
-			i = ABS(nb); i <<= 1;
+			i = ABS(nb); i *= 2;
 			while ( --i >= 0 ) *c++ = *b++;
 			return(0);
 		}
 		else if ( na == -1 ) {
 			*nc = - nb;
-			i = ABS(nb); i <<= 1;
+			i = ABS(nb); i *= 2;
 			while ( --i >= 0 ) *c++ = *b++;
 			return(0);
 		}
@@ -1232,12 +1232,12 @@ WORD RaisPow(PHEAD UWORD *a, WORD *na, UWORD b)
 	c = b;
 	for ( i = 0; i < BITSINWORD; i++ ) {
 		if ( !c ) break;
-		c >>= 1;
+		c /= 2;
 	}
 	i--;
 	c = 1 << i;
 	while ( --i >= 0 ) {
-		c >>= 1;
+		c /= 2;
 		if(MulLong(is,ns,is,ns,it,&nt)) goto RaisOvl;
 		if ( b & c ) {
 			if ( MulLong(it,nt,a,*na,is,&ns) ) goto RaisOvl;
@@ -1375,7 +1375,7 @@ WORD RaisPowMod (WORD x, WORD n, WORD m) {
 	while (n) {
 		if (n&1) { y*=z; y%=m; }
 		z*=z; z%=m;
-		n>>=1;
+		n /= 2;
 	}
 	return (WORD)y;
 }
@@ -2311,15 +2311,15 @@ WORD GcdLong(PHEAD UWORD *a, WORD na, UWORD *b, WORD nb, UWORD *c, WORD *nc)
 		while ( a[0] == 0 ) { a++; ana--; tcounta1++; }
 		for ( ii = 0; ii < ana; ii++ ) { *uw++ = *a++; }
 		if ( ( ana & 1 ) != 0 ) { *uw = 0; ana++; }
-		ana >>= 1;
+		ana /= 2;
 
 		u2 = uw = NumberMalloc("GcdLong");
 		upb = (mp_limb_t *)u2;
 		anb = nb; tcountb1 = 0;
 		while ( b[0] == 0 ) { b++; anb--; tcountb1++; }
 		for ( ii = 0; ii < anb; ii++ ) { *uw++ = *b++; }
 		if ( ( anb & 1 ) != 0 ) { *uw = 0; anb++; }
-		anb >>= 1;
+		anb /= 2;
 
 		xx = upa[0]; tcounta = 0;
 		while ( ( xx & 15 ) == 0 ) { tcounta += 4; xx >>= 4; }
@@ -3106,7 +3106,7 @@ WORD Modulus(WORD *term)
 		return(0);
 	}
 	else if ( n1 > 0 ) {
-		n1 <<= 1;
+		n1 *= 2;
 		t += n1;		/* Note that n1 >= 0 */
 		n1++;
 	}
@@ -3322,7 +3322,7 @@ WORD TakeNormalModulus (UWORD *a, WORD *na, UWORD *c, WORD nc, WORD par)
 	WCOPY(halfc,c,nc);
 
 	for (n=0; n<nhalfc; n++) {
-		halfc[n] >>= 1;
+		halfc[n] /= 2;
 		if (n+1<nc) halfc[n] |= c[n+1] << (BITSINWORD-1);
 	}
 
@@ -3393,11 +3393,11 @@ WORD MakeModTable()
 		UWORD *MMscrat7 = NumberMalloc("MakeModTable"), *MMscratC = NumberMalloc("MakeModTable");
 		*MMscratC = 1;
 		nScrat = 1;
-		j = size << 1;
+		j = size * 2;
 		for ( i = 0; i < j; i+=2 ) { AC.modpowers[i] = 0; AC.modpowers[i+1] = 0; }
 		for ( i = 0; i < size; i++ ) {
 			j = *MMscratC + (((LONG)MMscratC[1])<<BITSINWORD);
-			j <<= 1;
+			j *= 2;
 			AC.modpowers[j] = (WORD)(i & WORDMASK);
 			AC.modpowers[j+1] = (WORD)(i >> BITSINWORD);
 			MulLong((UWORD *)MMscratC,nScrat,(UWORD *)AC.powmod,
@@ -3406,7 +3406,7 @@ WORD MakeModTable()
 			*MMscratC = *MMscrat7; MMscratC[1] = MMscrat7[1]; nScrat = n2;
 		}
 		NumberFree(MMscrat7,"MakeModTable"); NumberFree(MMscratC,"MakeModTable");
-		j = size << 1;
+		j = size * 2;
 		for ( i = 4; i < j; i+=2 ) {
 			if ( AC.modpowers[i] == 0 && AC.modpowers[i+1] == 0 ) {
 				MLOCK(ErrorMessageLock);
@@ -3761,7 +3761,7 @@ void iniwranf(PHEAD0)
 		pow = offset; accu = 1;
 		while ( i ) {
 			if ( ( i & 1 ) != 0 ) accu *= pow;
-			i >>= 1; pow = pow*pow;
+			i /= 2; pow = pow*pow;
 		}
 		offset = accu;
 	}