Ok for google/main. A good candidate patch for trunk too.
Thanks,
David
On Tue, Jun 7, 2011 at 4:29 PM, Mark Heffernan <meh...@google.com> wrote:
> This patch pessimizes stack accounting during inlining. This enables
> setting a firm stack size limit (via parameters "large-stack-frame" and
> "large-stack-frame-growth"). Without this patch the inliner is overly
> optimistic about potential stack reuse resulting in actual stack frames much
> larger than the parameterized limits.
> Internal benchmarks show minor performance differences with non-fdo and
> lipo, but overall neutral. Tested/bootstrapped on x86-64.
> Ok for google-main?
> Mark
>
> 2011-06-07 Mark Heffernan <meh...@google.com>
> * cgraph.h (cgraph_global_info): Remove field.
> * ipa-inline.c (cgraph_clone_inlined_nodes): Change
> stack frame computation.
> (cgraph_check_inline_limits): Ditto.
> (compute_inline_parameters): Remove dead initialization.
>
> Index: gcc/cgraph.h
> ===================================================================
> --- gcc/cgraph.h (revision 174512)
> +++ gcc/cgraph.h (working copy)
> @@ -136,8 +136,6 @@ struct GTY(()) cgraph_local_info {
> struct GTY(()) cgraph_global_info {
> /* Estimated stack frame consumption by the function. */
> HOST_WIDE_INT estimated_stack_size;
> - /* Expected offset of the stack frame of inlined function. */
> - HOST_WIDE_INT stack_frame_offset;
>
> /* For inline clones this points to the function they will be
> inlined into. */
> Index: gcc/ipa-inline.c
> ===================================================================
> --- gcc/ipa-inline.c (revision 174512)
> +++ gcc/ipa-inline.c (working copy)
> @@ -229,8 +229,6 @@ void
> cgraph_clone_inlined_nodes (struct cgraph_edge *e, bool duplicate,
> bool update_original)
> {
> - HOST_WIDE_INT peak;
> -
> if (duplicate)
> {
> /* We may eliminate the need for out-of-line copy to be output.
> @@ -279,13 +277,13 @@ cgraph_clone_inlined_nodes (struct cgrap
> e->callee->global.inlined_to = e->caller->global.inlined_to;
> else
> e->callee->global.inlined_to = e->caller;
> - e->callee->global.stack_frame_offset
> - = e->caller->global.stack_frame_offset
> - + inline_summary (e->caller)->estimated_self_stack_size;
> - peak = e->callee->global.stack_frame_offset
> - + inline_summary (e->callee)->estimated_self_stack_size;
> - if (e->callee->global.inlined_to->global.estimated_stack_size < peak)
> - e->callee->global.inlined_to->global.estimated_stack_size = peak;
> +
> + /* Pessimistically assume no sharing of stack space. That is, the
> + frame size of a function is estimated as the original frame size
> + plus the sum of the frame sizes of all inlined callees. */
> + e->callee->global.inlined_to->global.estimated_stack_size +=
> + inline_summary (e->callee)->estimated_self_stack_size;
> +
> cgraph_propagate_frequency (e->callee);
>
> /* Recursively clone all bodies. */
> @@ -430,8 +428,7 @@ cgraph_check_inline_limits (struct cgrap
>
> stack_size_limit += stack_size_limit * PARAM_VALUE
> (PARAM_STACK_FRAME_GROWTH) / 100;
>
> - inlined_stack = (to->global.stack_frame_offset
> - + inline_summary (to)->estimated_self_stack_size
> + inlined_stack = (to->global.estimated_stack_size
> + what->global.estimated_stack_size);
> if (inlined_stack > stack_size_limit
> && inlined_stack > PARAM_VALUE (PARAM_LARGE_STACK_FRAME))
> @@ -2064,7 +2061,6 @@ compute_inline_parameters (struct cgraph
> self_stack_size = optimize ? estimated_stack_frame_size (node) : 0;
> inline_summary (node)->estimated_self_stack_size = self_stack_size;
> node->global.estimated_stack_size = self_stack_size;
> - node->global.stack_frame_offset = 0;
>
> /* Can this function be inlined at all? */
> node->local.inlinable = tree_inlinable_function_p (node->decl);
>
