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Diffstat (limited to 'gcc/doc/md.texi')
| -rw-r--r-- | gcc/doc/md.texi | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi index da5b799e6bc..ffb8843633e 100644 --- a/gcc/doc/md.texi +++ b/gcc/doc/md.texi @@ -4992,6 +4992,20 @@ some class of functions only requires one instruction to implement a return. Normally, the applicable functions are those which do not need to save any registers or allocate stack space. +It is valid for this pattern to expand to an instruction using +@code{simple_return} if no epilogue is required. + +@cindex @code{simple_return} instruction pattern +@item @samp{simple_return} +Subroutine return instruction. This instruction pattern name should be +defined only if a single instruction can do all the work of returning +from a function on a path where no epilogue is required. This pattern +is very similar to the @code{return} instruction pattern, but it is emitted +only by the shrink-wrapping optimization on paths where the function +prologue has not been executed, and a function return should occur without +any of the effects of the epilogue. Additional uses may be introduced on +paths where both the prologue and the epilogue have executed. + @findex reload_completed @findex leaf_function_p For such machines, the condition specified in this pattern should only |