ieee754/dbl-64: Reduce the scope of temporary storage variables

This came to light when adding hard-flaot support to ARC glibc port
without hardware sqrt support causing glibc build to fail:

| ../sysdeps/ieee754/dbl-64/e_sqrt.c: In function '__ieee754_sqrt':
| ../sysdeps/ieee754/dbl-64/e_sqrt.c:58:54: error: unused variable 'ty' [-Werror=unused-variable]
|   double y, t, del, res, res1, hy, z, zz, p, hx, tx, ty, s;

The reason being EMULV() macro uses the hardware provided
__builtin_fma() variant, leaving temporary variables 'p, hx, tx, hy, ty'
unused hence compiler warning and ensuing error.

The intent of the patch was to fix that error, but EMULV is pervasive
and used fair bit indirectly via othe rmacros, hence this patch.
Functionally it should not result in code gen changes and if at all
those would be better since the scope of those temporaries is greatly
reduced now

Built tested with aarch64-linux-gnu arm-linux-gnueabi arm-linux-gnueabihf hppa-linux-gnu x86_64-linux-gnu arm-linux-gnueabihf riscv64-linux-gnu-rv64imac-lp64 riscv64-linux-gnu-rv64imafdc-lp64 powerpc-linux-gnu microblaze-linux-gnu nios2-linux-gnu hppa-linux-gnu

Also as suggested by Joseph [1] used --strip and compared the libs with
and w/o patch and they are byte-for-byte unchanged (with gcc 9).

| for i in `find . -name libm-2.31.9000.so`;
| do
|    echo $i; diff $i /SCRATCH/vgupta/gnu2/install/glibcs/$i ; echo $?;
| done

| ./aarch64-linux-gnu/lib64/libm-2.31.9000.so
| 0
| ./arm-linux-gnueabi/lib/libm-2.31.9000.so
| 0
| ./x86_64-linux-gnu/lib64/libm-2.31.9000.so
| 0
| ./arm-linux-gnueabihf/lib/libm-2.31.9000.so
| 0
| ./riscv64-linux-gnu-rv64imac-lp64/lib64/lp64/libm-2.31.9000.so
| 0
| ./riscv64-linux-gnu-rv64imafdc-lp64/lib64/lp64/libm-2.31.9000.so
| 0
| ./powerpc-linux-gnu/lib/libm-2.31.9000.so
| 0
| ./microblaze-linux-gnu/lib/libm-2.31.9000.so
| 0
| ./nios2-linux-gnu/lib/libm-2.31.9000.so
| 0
| ./hppa-linux-gnu/lib/libm-2.31.9000.so
| 0
| ./s390x-linux-gnu/lib64/libm-2.31.9000.so

[1] https://sourceware.org/pipermail/libc-alpha/2019-November/108267.html

1 files changed, 19 insertions, 15 deletions

diff --git a/sysdeps/ieee754/dbl-64/dla.h b/sysdeps/ieee754/dbl-64/dla.h
index 1bbad16..fd58664 100644
--- a/sysdeps/ieee754/dbl-64/dla.h
+++ b/sysdeps/ieee754/dbl-64/dla.h
@@ -67,13 +67,15 @@
 /* storage variables of type double.                                   */
 
 #ifdef DLA_FMS
-# define  EMULV(x, y, z, zz, p, hx, tx, hy, ty)          \
+# define  EMULV(x, y, z, zz)          \
   z = x * y; zz = DLA_FMS (x, y, z);
 #else
-# define  EMULV(x, y, z, zz, p, hx, tx, hy, ty)          \
-  p = CN * (x);  hx = ((x) - p) + p;  tx = (x) - hx; \
-  p = CN * (y);  hy = ((y) - p) + p;  ty = (y) - hy; \
-  z = (x) * (y); zz = (((hx * hy - z) + hx * ty) + tx * hy) + tx * ty;
+# define  EMULV(x, y, z, zz)          \
+    ({  __typeof__ (x) __p, hx, tx, hy, ty;          \
+        __p = CN * (x);  hx = ((x) - __p) + __p;  tx = (x) - hx; \
+        __p = CN * (y);  hy = ((y) - __p) + __p;  ty = (y) - hy; \
+        z = (x) * (y); zz = (((hx * hy - z) + hx * ty) + tx * hy) + tx * ty; \
+    })
 #endif
 
 
@@ -83,13 +85,15 @@
 /* storage variables of type double.                                         */
 
 #ifdef DLA_FMS
-# define  MUL12(x,y,z,zz,p,hx,tx,hy,ty,q)        \
-	   EMULV(x,y,z,zz,p,hx,tx,hy,ty)
+# define  MUL12(x, y, z, zz)        \
+	   EMULV(x, y, z, zz)
 #else
-# define  MUL12(x,y,z,zz,p,hx,tx,hy,ty,q)        \
-	   p=CN*(x);  hx=((x)-p)+p;  tx=(x)-hx; \
-	   p=CN*(y);  hy=((y)-p)+p;  ty=(y)-hy; \
-	   p=hx*hy;  q=hx*ty+tx*hy; z=p+q;  zz=((p-z)+q)+tx*ty;
+# define  MUL12(x, y, z, zz)        \
+    ({  __typeof__ (x) __p, hx, tx, hy, ty, __q; \
+	   __p=CN*(x);  hx=((x)-__p)+__p;  tx=(x)-hx;  \
+	   __p=CN*(y);  hy=((y)-__p)+__p;  ty=(y)-hy;  \
+	   __p=hx*hy;  __q=hx*ty+tx*hy; z=__p+__q;  zz=((__p-z)+__q)+tx*ty; \
+    })
 #endif
 
 
@@ -125,8 +129,8 @@
 /* are assumed to be double-length numbers. p,hx,tx,hy,ty,q,c,cc are         */
 /* temporary storage variables of type double.                               */
 
-#define  MUL2(x, xx, y, yy, z, zz, p, hx, tx, hy, ty, q, c, cc)  \
-  MUL12 (x, y, c, cc, p, hx, tx, hy, ty, q)                      \
+#define  MUL2(x, xx, y, yy, z, zz, c, cc)  \
+  MUL12 (x, y, c, cc);                     \
   cc = ((x) * (yy) + (xx) * (y)) + cc;   z = c + cc;   zz = (c - z) + cc;
 
 
@@ -136,8 +140,8 @@
 /* are assumed to be double-length numbers. p,hx,tx,hy,ty,q,c,cc,u,uu        */
 /* are temporary storage variables of type double.                           */
 
-#define  DIV2(x,xx,y,yy,z,zz,p,hx,tx,hy,ty,q,c,cc,u,uu)  \
-	   c=(x)/(y);   MUL12(c,y,u,uu,p,hx,tx,hy,ty,q)  \
+#define  DIV2(x, xx, y, yy, z, zz, c, cc, u, uu)  \
+	   c=(x)/(y);   MUL12(c,y,u,uu);          \
 	   cc=(((((x)-u)-uu)+(xx))-c*(yy))/(y);   z=c+cc;   zz=(c-z)+cc;