-@ifset ELF
-When using ELF, the @code{.comm} directive takes an optional third argument.
-This is the desired alignment of the symbol, specified as a byte boundary (for
-example, an alignment of 16 means that the least significant 4 bits of the
-address should be zero). The alignment must be an absolute expression, and it
-must be a power of two. If @code{@value{LD}} allocates uninitialized memory
-for the common symbol, it will use the alignment when placing the symbol. If
-no alignment is specified, @command{@value{AS}} will set the alignment to the
+@ifset COFF-ELF
+When using ELF or (as a GNU extension) PE, the @code{.comm} directive takes
+an optional third argument. This is the desired alignment of the symbol,
+specified for ELF as a byte boundary (for example, an alignment of 16 means
+that the least significant 4 bits of the address should be zero), and for PE
+as a power of two (for example, an alignment of 5 means aligned to a 32-byte
+boundary). The alignment must be an absolute expression, and it must be a
+power of two. If @code{@value{LD}} allocates uninitialized memory for the
+common symbol, it will use the alignment when placing the symbol. If no
+alignment is specified, @command{@value{AS}} will set the alignment to the