Fix strict-aliasing issues with _strtod_r and Storeinc.

	* libc/stdlib/strtod.c (_strtod_r): Change local variables aadj,
	rv, rv0 from double to type U.  Use accessor macros dval, dword0
	and dword1 for all accesses except for the ULtod call, where rv.i
	replaces the pointer cast.
	* libc/stdlib/mprec.h (U): Rename member L to i for easier re-use
	of access macros.  Tweak comment.
	Remove #ifdef'd YES_ALIAS code.
	(dword0, dword1, dval): Define in terms of uncast union member
	access.  Ditto for _DOUBLE_IS_32BITS variants.
	(Storeinc): Replace aliasing-flawed microoptimized definition with
	alternative suggested in comment.  Remove now stale comment.

1 files changed, 21 insertions, 20 deletions

diff --git a/newlib/libc/stdlib/strtod.c b/newlib/libc/stdlib/strtod.c
index 80e5aac..703fbce 100644
--- a/newlib/libc/stdlib/strtod.c
+++ b/newlib/libc/stdlib/strtod.c
@@ -218,7 +218,8 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 	int bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, decpt, dsign,
 		 e, e1, esign, i, j, k, nd, nd0, nf, nz, nz0, sign;
 	_CONST char *s, *s0, *s1;
-	double aadj, aadj1, adj, rv, rv0;
+	double aadj, adj;
+	U aadj1, rv, rv0;
 	Long L;
 	__ULong y, z;
 	_Bigint *bb, *bb1, *bd, *bd0, *bs, *delta;
@@ -286,7 +287,7 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 					copybits(bits, fpi.nbits, bb);
 					Bfree(ptr,bb);
 					}
-				ULtod(((U*)&rv)->L, bits, exp, i);
+				ULtod(rv.i, bits, exp, i);
 			  }}
 			goto ret;
 		  }
@@ -469,7 +470,7 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 #ifdef Honor_FLT_ROUNDS
 				/* round correctly FLT_ROUNDS = 2 or 3 */
 				if (sign) {
-					rv = -rv;
+					dval(rv) = -dval(rv);
 					sign = 0;
 					}
 #endif
@@ -485,7 +486,7 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 #ifdef Honor_FLT_ROUNDS
 				/* round correctly FLT_ROUNDS = 2 or 3 */
 				if (sign) {
-					rv = -rv;
+					dval(rv) = -dval(rv);
 					sign = 0;
 					}
 #endif
@@ -513,7 +514,7 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 #ifdef Honor_FLT_ROUNDS
 			/* round correctly FLT_ROUNDS = 2 or 3 */
 			if (sign) {
-				rv = -rv;
+				dval(rv) = -dval(rv);
 				sign = 0;
 				}
 #endif
@@ -976,14 +977,14 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 			}
 		if ((aadj = ratio(delta, bs)) <= 2.) {
 			if (dsign)
-				aadj = aadj1 = 1.;
+				aadj = dval(aadj1) = 1.;
 			else if (dword1(rv) || dword0(rv) & Bndry_mask) {
 #ifndef Sudden_Underflow
 				if (dword1(rv) == Tiny1 && !dword0(rv))
 					goto undfl;
 #endif
 				aadj = 1.;
-				aadj1 = -1.;
+				dval(aadj1) = -1.;
 				}
 			else {
 				/* special case -- power of FLT_RADIX to be */
@@ -993,24 +994,24 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 					aadj = 1./FLT_RADIX;
 				else
 					aadj *= 0.5;
-				aadj1 = -aadj;
+				dval(aadj1) = -aadj;
 				}
 			}
 		else {
 			aadj *= 0.5;
-			aadj1 = dsign ? aadj : -aadj;
+			dval(aadj1) = dsign ? aadj : -aadj;
 #ifdef Check_FLT_ROUNDS
 			switch(Rounding) {
 				case 2: /* towards +infinity */
-					aadj1 -= 0.5;
+					dval(aadj1) -= 0.5;
 					break;
 				case 0: /* towards 0 */
 				case 3: /* towards -infinity */
-					aadj1 += 0.5;
+					dval(aadj1) += 0.5;
 				}
 #else
 			if (Flt_Rounds == 0)
-				aadj1 += 0.5;
+				dval(aadj1) += 0.5;
 #endif /*Check_FLT_ROUNDS*/
 			}
 		y = dword0(rv) & Exp_mask;
@@ -1020,7 +1021,7 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 		if (y == Exp_msk1*(DBL_MAX_EXP+Bias-1)) {
 			dval(rv0) = dval(rv);
 			dword0(rv) -= P*Exp_msk1;
-			adj = aadj1 * ulp(dval(rv));
+			adj = dval(aadj1) * ulp(dval(rv));
 			dval(rv) += adj;
 			if ((dword0(rv) & Exp_mask) >=
 					Exp_msk1*(DBL_MAX_EXP+Bias-P)) {
@@ -1042,18 +1043,18 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 					if ((z = aadj) <= 0)
 						z = 1;
 					aadj = z;
-					aadj1 = dsign ? aadj : -aadj;
+					dval(aadj1) = dsign ? aadj : -aadj;
 					}
 				dword0(aadj1) += (2*P+1)*Exp_msk1 - y;
 				}
-			adj = aadj1 * ulp(dval(rv));
+			adj = dval(aadj1) * ulp(dval(rv));
 			dval(rv) += adj;
 #else
 #ifdef Sudden_Underflow
 			if ((dword0(rv) & Exp_mask) <= P*Exp_msk1) {
 				dval(rv0) = dval(rv);
 				dword0(rv) += P*Exp_msk1;
-				adj = aadj1 * ulp(dval(rv));
+				adj = dval(aadj1) * ulp(dval(rv));
 				dval(rv) += adj;
 #ifdef IBM
 				if ((dword0(rv) & Exp_mask) <  P*Exp_msk1)
@@ -1076,7 +1077,7 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 					dword0(rv) -= P*Exp_msk1;
 				}
 			else {
-				adj = aadj1 * ulp(dval(rv));
+				adj = dval(aadj1) * ulp(dval(rv));
 				dval(rv) += adj;
 				}
 #else /*Sudden_Underflow*/
@@ -1088,11 +1089,11 @@ _DEFUN (_strtod_r, (ptr, s00, se),
 			 * example: 1.2e-307 .
 			 */
 			if (y <= (P-1)*Exp_msk1 && aadj > 1.) {
-				aadj1 = (double)(int)(aadj + 0.5);
+				dval(aadj1) = (double)(int)(aadj + 0.5);
 				if (!dsign)
-					aadj1 = -aadj1;
+					dval(aadj1) = -dval(aadj1);
 				}
-			adj = aadj1 * ulp(dval(rv));
+			adj = dval(aadj1) * ulp(dval(rv));
 			dval(rv) += adj;
 #endif /*Sudden_Underflow*/
 #endif /*Avoid_Underflow*/