expr.c (STACK_BYTES): Delete unused macro.

[thirdparty/gcc.git] / gcc / tm.texi

diff --git a/gcc/tm.texi b/gcc/tm.texi
index ab35f1f75985c1193a7ae49e3020d47ff90a4af1..7a0dd0e4756b3b4e6ac8ad2db5f12b919a9ac8ba 100644 (file)
--- a/gcc/tm.texi
+++ b/gcc/tm.texi
@@ -790,15 +790,24 @@ size of an integer.
 
 @findex STACK_BOUNDARY
 @item STACK_BOUNDARY
+Define this macro if there is a guaranteed alignment for the stack
+pointer on this machine.  The definition is a C expression
+for the desired alignment (measured in bits).  This value is used as a
+default if PREFERRED_STACK_BOUNDARY is not defined.
+
+@findex PREFERRED_STACK_BOUNDARY
+@item PREFERRED_STACK_BOUNDARY
 Define this macro if you wish to preserve a certain alignment for
 the stack pointer.  The definition is a C expression
-for the desired alignment (measured in bits).
+for the desired alignment (measured in bits).  If STACK_BOUNDARY is
+also defined, this macro must evaluate to a value equal to or larger
+than STACK_BOUNDARY.
 
-@cindex @code{PUSH_ROUNDING}, interaction with @code{STACK_BOUNDARY}
+@cindex @code{PUSH_ROUNDING}, interaction with @code{PREFERRED_STACK_BOUNDARY}
 If @code{PUSH_ROUNDING} is not defined, the stack will always be aligned
-to the specified boundary.  If @code{PUSH_ROUNDING} is defined and specifies a
-less strict alignment than @code{STACK_BOUNDARY}, the stack may be
-momentarily unaligned while pushing arguments.
+to the specified boundary.  If @code{PUSH_ROUNDING} is defined and specifies
+a less strict alignment than @code{PREFERRED_STACK_BOUNDARY}, the stack may
+be momentarily unaligned while pushing arguments.
 
 @findex FUNCTION_BOUNDARY
 @item FUNCTION_BOUNDARY