Introduce can_implement_as_sibling_call_p
gcc/ChangeLog: * calls.c (expand_call): Move "Rest of purposes for tail call optimizations to fail" to... (can_implement_as_sibling_call_p): ...this new function, and split into multiple "if" statements. From-SVN: r236513
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David Malcolm
David Malcolm
parent
97c53806a2
commit
b40d90e6c5
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@ -1,3 +1,10 @@
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2016-05-20 David Malcolm <dmalcolm@redhat.com>
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* calls.c (expand_call): Move "Rest of purposes for tail call
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optimizations to fail" to...
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(can_implement_as_sibling_call_p): ...this new function, and
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split into multiple "if" statements.
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2016-05-20 Jan Hubicka <hubicka@ucw.cz>
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* cfgloop.h (expected_loop_iterations_unbounded,
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114
gcc/calls.c
114
gcc/calls.c
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@ -2344,6 +2344,78 @@ avoid_likely_spilled_reg (rtx x)
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return x;
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}
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/* Helper function for expand_call.
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Return false is EXP is not implementable as a sibling call. */
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static bool
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can_implement_as_sibling_call_p (tree exp,
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rtx structure_value_addr,
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tree funtype,
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int reg_parm_stack_space,
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tree fndecl,
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int flags,
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tree addr,
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const args_size &args_size)
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{
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if (!targetm.have_sibcall_epilogue ())
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return false;
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/* Doing sibling call optimization needs some work, since
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structure_value_addr can be allocated on the stack.
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It does not seem worth the effort since few optimizable
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sibling calls will return a structure. */
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if (structure_value_addr != NULL_RTX)
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return false;
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#ifdef REG_PARM_STACK_SPACE
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/* If outgoing reg parm stack space changes, we can not do sibcall. */
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if (OUTGOING_REG_PARM_STACK_SPACE (funtype)
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!= OUTGOING_REG_PARM_STACK_SPACE (TREE_TYPE (current_function_decl))
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|| (reg_parm_stack_space != REG_PARM_STACK_SPACE (current_function_decl)))
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return false;
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#endif
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/* Check whether the target is able to optimize the call
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into a sibcall. */
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if (!targetm.function_ok_for_sibcall (fndecl, exp))
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return false;
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/* Functions that do not return exactly once may not be sibcall
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optimized. */
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if (flags & (ECF_RETURNS_TWICE | ECF_NORETURN))
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return false;
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if (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (addr))))
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return false;
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/* If the called function is nested in the current one, it might access
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some of the caller's arguments, but could clobber them beforehand if
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the argument areas are shared. */
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if (fndecl && decl_function_context (fndecl) == current_function_decl)
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return false;
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/* If this function requires more stack slots than the current
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function, we cannot change it into a sibling call.
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crtl->args.pretend_args_size is not part of the
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stack allocated by our caller. */
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if (args_size.constant > (crtl->args.size - crtl->args.pretend_args_size))
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return false;
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/* If the callee pops its own arguments, then it must pop exactly
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the same number of arguments as the current function. */
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if (targetm.calls.return_pops_args (fndecl, funtype, args_size.constant)
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!= targetm.calls.return_pops_args (current_function_decl,
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TREE_TYPE (current_function_decl),
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crtl->args.size))
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return false;
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if (!lang_hooks.decls.ok_for_sibcall (fndecl))
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return false;
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/* All checks passed. */
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return true;
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}
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/* Generate all the code for a CALL_EXPR exp
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and return an rtx for its value.
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Store the value in TARGET (specified as an rtx) if convenient.
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@ -2740,44 +2812,10 @@ expand_call (tree exp, rtx target, int ignore)
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try_tail_call = 0;
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/* Rest of purposes for tail call optimizations to fail. */
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if (!try_tail_call
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|| !targetm.have_sibcall_epilogue ()
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/* Doing sibling call optimization needs some work, since
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structure_value_addr can be allocated on the stack.
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It does not seem worth the effort since few optimizable
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sibling calls will return a structure. */
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|| structure_value_addr != NULL_RTX
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#ifdef REG_PARM_STACK_SPACE
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/* If outgoing reg parm stack space changes, we can not do sibcall. */
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|| (OUTGOING_REG_PARM_STACK_SPACE (funtype)
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!= OUTGOING_REG_PARM_STACK_SPACE (TREE_TYPE (current_function_decl)))
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|| (reg_parm_stack_space != REG_PARM_STACK_SPACE (current_function_decl))
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#endif
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/* Check whether the target is able to optimize the call
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into a sibcall. */
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|| !targetm.function_ok_for_sibcall (fndecl, exp)
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/* Functions that do not return exactly once may not be sibcall
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optimized. */
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|| (flags & (ECF_RETURNS_TWICE | ECF_NORETURN))
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|| TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (addr)))
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/* If the called function is nested in the current one, it might access
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some of the caller's arguments, but could clobber them beforehand if
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the argument areas are shared. */
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|| (fndecl && decl_function_context (fndecl) == current_function_decl)
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/* If this function requires more stack slots than the current
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function, we cannot change it into a sibling call.
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crtl->args.pretend_args_size is not part of the
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stack allocated by our caller. */
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|| args_size.constant > (crtl->args.size
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- crtl->args.pretend_args_size)
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/* If the callee pops its own arguments, then it must pop exactly
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the same number of arguments as the current function. */
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|| (targetm.calls.return_pops_args (fndecl, funtype, args_size.constant)
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!= targetm.calls.return_pops_args (current_function_decl,
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TREE_TYPE (current_function_decl),
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crtl->args.size))
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|| !lang_hooks.decls.ok_for_sibcall (fndecl))
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try_tail_call = 0;
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if (try_tail_call)
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try_tail_call = can_implement_as_sibling_call_p (exp, structure_value_addr, funtype,
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reg_parm_stack_space, fndecl,
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flags, addr, args_size);
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/* Check if caller and callee disagree in promotion of function
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return value. */
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