tm.texi.in (TARGET_RTX_COSTS): Add an opno paramter.

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

diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index d383ecaa6b20352c52e6843ac8d6f43e46bea36b..832aefef4f1ce92b4cd02feea042a5fd13e5dc0a 100644 (file)
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -6415,14 +6415,19 @@ Define this macro if a non-short-circuit operation produced by
 @code{BRANCH_COST} is greater than or equal to the value 2.
 @end defmac
 
-@deftypefn {Target Hook} bool TARGET_RTX_COSTS (rtx @var{x}, int @var{code}, int @var{outer_code}, int *@var{total}, bool @var{speed})
+@deftypefn {Target Hook} bool TARGET_RTX_COSTS (rtx @var{x}, int @var{code}, int @var{outer_code}, int @var{opno}, int *@var{total}, bool @var{speed})
 This target hook describes the relative costs of RTL expressions.
 
 The cost may depend on the precise form of the expression, which is
-available for examination in @var{x}, and the rtx code of the expression
-in which it is contained, found in @var{outer_code}.  @var{code} is the
-expression code---redundant, since it can be obtained with
-@code{GET_CODE (@var{x})}.
+available for examination in @var{x}, and the fact that @var{x} appears
+as operand @var{opno} of an expression with rtx code @var{outer_code}.
+That is, the hook can assume that there is some rtx @var{y} such
+that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that
+either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or
+(b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.
+
+@var{code} is @var{x}'s expression code---redundant, since it can be
+obtained with @code{GET_CODE (@var{x})}.
 
 In implementing this hook, you can use the construct
 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast