re PR middle-end/90553 (Register allocation allocates post-incremented address-load of call to call-clobbered register)

	PR middle-end/90553
	* ira-lives.c (process_bb_node_lives): Consider defs
	for a call insn to be die before the call, not after.

From-SVN: r271498

2 files changed, 15 insertions, 5 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9c4c215..e5e0fe18 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,9 @@
 2019-05-22  Hans-Peter Nilsson  <hp@axis.com>
 
+	PR middle-end/90553
+	* ira-lives.c (process_bb_node_lives): Consider defs
+	for a call insn to be die before the call, not after.
+
 	* function.c (assign_parm_setup_block): Raise alignment of
 	stacked parameter only for STRICT_ALIGNMENT targets.
 
diff --git a/gcc/ira-lives.c b/gcc/ira-lives.c
index faadf08..581fdd3 100644
--- a/gcc/ira-lives.c
+++ b/gcc/ira-lives.c
@@ -1241,11 +1241,6 @@ process_bb_node_lives (ira_loop_tree_node_t loop_tree_node)
 	  preprocess_constraints (insn);
 	  process_single_reg_class_operands (false, freq);
 
-	  /* See which defined values die here.  */
-	  FOR_EACH_INSN_DEF (def, insn)
-	    if (!call_p || !DF_REF_FLAGS_IS_SET (def, DF_REF_MAY_CLOBBER))
-	      mark_ref_dead (def);
-
 	  if (call_p)
 	    {
 	      /* Try to find a SET in the CALL_INSN_FUNCTION_USAGE, and from
@@ -1309,6 +1304,17 @@ process_bb_node_lives (ira_loop_tree_node_t loop_tree_node)
 		}
 	    }
 
+	  /* See which defined values die here.  Note that we include
+	     the call insn in the lifetimes of these values, so we don't
+	     mistakenly consider, for e.g. an addressing mode with a
+	     side-effect like a post-increment fetching the address,
+	     that the use happens before the call, and the def to happen
+	     after the call: we believe both to happen before the actual
+	     call.  (We don't handle return-values here.)  */
+	  FOR_EACH_INSN_DEF (def, insn)
+	    if (!call_p || !DF_REF_FLAGS_IS_SET (def, DF_REF_MAY_CLOBBER))
+	      mark_ref_dead (def);
+
 	  make_early_clobber_and_input_conflicts ();
 
 	  curr_point++;