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Diffstat (limited to 'gcc/doc/tm.texi')
| -rw-r--r-- | gcc/doc/tm.texi | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi index 3087694a9cd..2cd0877601d 100644 --- a/gcc/doc/tm.texi +++ b/gcc/doc/tm.texi @@ -5874,9 +5874,14 @@ value to the result of that function. The arguments to that function are the same as to this macro. @end defmac -@defmac BRANCH_COST -A C expression for the cost of a branch instruction. A value of 1 is -the default; other values are interpreted relative to that. +@defmac BRANCH_COST (@var{speed_p}, @var{predictable_p}) +A C expression for the cost of a branch instruction. A value of 1 is the +default; other values are interpreted relative to that. Parameter @var{speed_p} +is true when the branch in question should be optimized for speed. When +it is false, @code{BRANCH_COST} should be returning value optimal for code size +rather then performance considerations. @var{predictable_p} is true for well +predictable branches. On many architectures the @code{BRANCH_COST} can be +reduced then. @end defmac Here are additional macros which do not specify precise relative costs, |