From: Richard Biener <rguenther@suse.de>
Date: Fri, 29 Jan 2021 15:02:36 +0000 (+0100)
Subject: rtl-optimization/98863 - tame i386 specific RPAD pass
X-Git-Tag: releases/gcc-10.3.0~323
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=550bf0c50024c320b7010d1b2bf644c5c918ad98;p=thirdparty%2Fgcc.git

rtl-optimization/98863 - tame i386 specific RPAD pass

This removes analyzing DF with expensive problems which we do not
use at all and which somehow cause 5GB of memory to leak.  Instead
just do a defered rescan of added insns.

This avoids

> FAIL: gcc.c-torture/compile/20051216-1.c   -O1  (internal compiler error)
> FAIL: gcc.c-torture/compile/20051216-1.c   -O1  (test for excess errors)

by clearing DF_DEFER_INSN_RESCAN after calling df_process_deferred_rescans,
so that it doesn't leak into following unprepared passes that expect
non-deferred rescans.

2021-02-03  Richard Biener  <rguenther@suse.de>
	    Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/98863
	* config/i386/i386-features.c (remove_partial_avx_dependency):
	Do not perform DF analysis.
	(pass_data_remove_partial_avx_dependency): Remove
	TODO_df_finish.

	* gcc.target/i386/20051216-1.c: New test.
---

diff --git a/gcc/config/i386/i386-features.c b/gcc/config/i386/i386-features.c
index b1109de7cb61..ecc8c014aca3 100644
--- a/gcc/config/i386/i386-features.c
+++ b/gcc/config/i386/i386-features.c
@@ -2143,6 +2143,9 @@ remove_partial_avx_dependency (void)
 
   auto_vec<rtx_insn *> control_flow_insns;
 
+  /* We create invalid RTL initially so defer rescans.  */
+  df_set_flags (DF_DEFER_INSN_RESCAN);
+
   FOR_EACH_BB_FN (bb, cfun)
     {
       FOR_BB_INSNS (bb, insn)
@@ -2159,14 +2162,7 @@ remove_partial_avx_dependency (void)
 	    continue;
 
 	  if (!v4sf_const0)
-	    {
-	      calculate_dominance_info (CDI_DOMINATORS);
-	      df_set_flags (DF_DEFER_INSN_RESCAN);
-	      df_chain_add_problem (DF_DU_CHAIN | DF_UD_CHAIN);
-	      df_md_add_problem ();
-	      df_analyze ();
-	      v4sf_const0 = gen_reg_rtx (V4SFmode);
-	    }
+	    v4sf_const0 = gen_reg_rtx (V4SFmode);
 
 	  /* Convert PARTIAL_XMM_UPDATE_TRUE insns, DF -> SF, SF -> DF,
 	     SI -> SF, SI -> DF, DI -> SF, DI -> DF, to vec_dup and
@@ -2227,6 +2223,7 @@ remove_partial_avx_dependency (void)
     {
       /* (Re-)discover loops so that bb->loop_father can be used in the
 	 analysis below.  */
+      calculate_dominance_info (CDI_DOMINATORS);
       loop_optimizer_init (AVOID_CFG_MODIFICATIONS);
 
       /* Generate a vxorps at entry of the nearest dominator for basic
@@ -2258,7 +2255,6 @@ remove_partial_avx_dependency (void)
 	set_insn = emit_insn_after (set,
 				    insn ? PREV_INSN (insn) : BB_END (bb));
       df_insn_rescan (set_insn);
-      df_process_deferred_rescans ();
       loop_optimizer_finalize ();
 
       if (!control_flow_insns.is_empty ())
@@ -2279,6 +2275,8 @@ remove_partial_avx_dependency (void)
 	}
     }
 
+  df_process_deferred_rescans ();
+  df_clear_flags (DF_DEFER_INSN_RESCAN);
   bitmap_obstack_release (NULL);
   BITMAP_FREE (convert_bbs);
 
@@ -2298,7 +2296,7 @@ const pass_data pass_data_remove_partial_avx_dependency =
   0, /* properties_provided */
   0, /* properties_destroyed */
   0, /* todo_flags_start */
-  TODO_df_finish, /* todo_flags_finish */
+  0, /* todo_flags_finish */
 };
 
 class pass_remove_partial_avx_dependency : public rtl_opt_pass
diff --git a/gcc/testsuite/gcc.target/i386/20051216-1.c b/gcc/testsuite/gcc.target/i386/20051216-1.c
new file mode 100644
index 000000000000..42a31d0936e5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/20051216-1.c
@@ -0,0 +1,5 @@
+/* PR rtl-optimization/25432 */
+/* { dg-do compile } */
+/* { dg-options "-O1 -march=cascadelake" } */
+
+#include "../../gcc.c-torture/compile/20051216-1.c"