* rtl.h (INSN_P): New macro.

	(successor_phi_fn): New typedef.
	(for_each_successor_phi): New prototype.
	(in_ssa_form): New variable.
	(PHI_NODE_P): Likewise.
	* flow.c (calculate_global_regs_live): Add to new_live_at_end from
	phi nodes in successors.
	(mark_used_regs): Add PHI case.
	(set_phi_alternative_reg): New function.
	(life_analysis): Assert that dead code elimination is not selected
	when in SSA form.
	* toplev.c (to_ssa_time): New variable.
	(from_ssa_time): Likewise.
	(compile_file): Zero to_ssa_time and from_ssa_time.
	Print time to convert to and from SSA.
	(rest_of_compilation): Time convert_to_ssa and convert_from_ssa.
	(print_time): Compute percent fraction as integer.
	* ssa.c (PHI_NODE_P): Moved to rtl.h.
	(convert_to_ssa): Check if we're already in SSA.
	Don't eliminate dead code in life_analysis.
	Rerun flow and life analysis at bottom.
	(eliminate_phi): Use canonical regnos when adding nodes.
	(mark_reg_in_phi): New function.
	(mark_phi_and_copy_regs): Likewise.
	(convert_from_ssa): Rerun life analysis at top.
	Use coalesced partition.
	Check for removing a phi node at the end of the block.
	(compute_coalesced_reg_partition): New function.
	(coalesce_regs_in_copies): Likewise.
	(coalesce_reg_in_phi): Likewise.
	(coalesce_regs_in_sucessor_phi_nodes): Likewise.
	(for_each_successor_phi): Likewise.
	(rename_context): New struct.
	(rename_block): Use a rename_context with rename_insn_1.  When
	renaming sets of a subreg, emit a copy of the entire reg first.
	(rename_insn_1): Treat data as a rename_context *.  Save current
	insn in set_data.
	(rename_set_data): Add field set_insn.
	* Makefile.in (HASHTAB_H): Move up in file.
	(OBSTACK_H): New macro.
	(collect2.o): Use OBSTACK_H in dependencies.
	(sdbout.o): Likewise.
	(emit-rtl.o): Likewise.
	(simplify-rtx.o): Likewise.
	(fix-header.o): Likewise.
	(OBJS):	Add conflict.o.
	(conflict.o): New rule.
	* basic-block.h: Include partition.h.
	(conflict_graph): New typedef.
	(conflict_graph_enum_fn): Likewise.
	(conflict_graph_new): New prototype.
	(conflict_graph_delete): Likewise.
	(conflict_graph_add): Likewise.
	(conflict_graph_conflict_p): Likewise.
	(conflict_graph_enum): Likewise.
	(conflict_graph_merge_regs): Likewise.
	(conflict_graph_print): Likewise.
	(conflict_graph_compute): Likewise.
	* conflict.c: New file.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@32979 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 40 insertions, 0 deletions

diff --git a/gcc/flow.c b/gcc/flow.c
index 32693e41d71..4fd65dca569 100644
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -317,6 +317,7 @@ static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
 static void notice_stack_pointer_modification PARAMS ((rtx));
 static void mark_reg			PARAMS ((rtx, void *));
 static void mark_regs_live_at_end	PARAMS ((regset));
+static int set_phi_alternative_reg      PARAMS ((rtx, int, int, void *));
 static void calculate_global_regs_live	PARAMS ((sbitmap, sbitmap, int));
 static void propagate_block		PARAMS ((basic_block, regset,
 						 regset, int));
@@ -2486,6 +2487,15 @@ life_analysis (f, nregs, file, remove_dead_code)
 #endif
   int flags;
   sbitmap all_blocks;
+
+  /* Dead code elimination changes basic block structure and therefore
+     breaks the SSA phi representation.  Particularly, a phi node
+     can have an alternative value for each incoming block, referenced
+     by the block number.  Removing dead code can bump entire blocks
+     and therefore cause blocks to be renumbered, invalidating the
+     numbering of phi alternatives.  */
+  if (remove_dead_code && in_ssa_form)
+    abort ();
  
   /* Record which registers will be eliminated.  We use this in
      mark_used_regs.  */
@@ -2960,6 +2970,22 @@ mark_regs_live_at_end (set)
   diddle_return_value (mark_reg, set);
 }
 
+/* Callback function for for_each_successor_phi.  DATA is a regset.
+   Sets the SRC_REGNO, the regno of the phi alternative for phi node
+   INSN, in the regset.  */
+
+static int
+set_phi_alternative_reg (insn, dest_regno, src_regno, data)
+     rtx insn ATTRIBUTE_UNUSED;
+     int dest_regno ATTRIBUTE_UNUSED;
+     int src_regno;
+     void *data;
+{
+  regset live = (regset) data;
+  SET_REGNO_REG_SET (live, src_regno);
+  return 0;
+}
+
 /* Propagate global life info around the graph of basic blocks.  Begin
    considering blocks with their corresponding bit set in BLOCKS_IN. 
    BLOCKS_OUT is set for every block that was changed.  */
@@ -3020,6 +3046,13 @@ calculate_global_regs_live (blocks_in, blocks_out, flags)
 	  IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
 	}
 
+      /* Regs used in phi nodes are not included in
+	 global_live_at_start, since they are live only along a
+	 particular edge.  Set those regs that are live because of a
+	 phi node alternative corresponding to this particular block.  */
+      for_each_successor_phi (bb->index, &set_phi_alternative_reg, 
+			      new_live_at_end);
+
       if (bb == ENTRY_BLOCK_PTR)
 	{
 	  COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
@@ -4688,6 +4721,13 @@ mark_used_regs (needed, live, x, flags, insn)
 	break;
       }
 
+    case PHI:
+      /* We _do_not_ want to scan operands of phi nodes.  Operands of
+	 a phi function are evaluated only when control reaches this
+	 block along a particular edge.  Therefore, regs that appear
+	 as arguments to phi should not be added to the global live at
+	 start.  */
+      return;
 
     default:
       break;