From: Richard Biener <rguenther@suse.de>
Date: Fri, 26 Jan 2018 14:50:25 +0000 (+0000)
Subject: re PR rtl-optimization/84003 (FAIL: g++.dg/torture/pr77745.C with noinline foo)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d7e1f499ed046bd1d57eaf4510778d2fc2666653;p=gcc.git

re PR rtl-optimization/84003 (FAIL: g++.dg/torture/pr77745.C with noinline foo)

2018-01-26  Richard Biener  <rguenther@suse.de>

	PR rtl-optimization/84003
	* dse.c (record_store): Only record redundant stores when
	the earlier store aliases at least all accesses the later one does.

	* g++.dg/torture/pr77745.C: Mark foo noinline to trigger
	latent bug in DSE if NOINLINE is appropriately defined.
	* g++.dg/torture/pr77745-2.C: New testcase including pr77745.C
	and defining NOINLINE.

From-SVN: r257091
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 764368ae20a..2f6426927a5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-01-26  Richard Biener  <rguenther@suse.de>
+
+	PR rtl-optimization/84003
+	* dse.c (record_store): Only record redundant stores when
+	the earlier store aliases at least all accesses the later one does.
+
 2018-01-26  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/83985
diff --git a/gcc/dse.c b/gcc/dse.c
index a0c66aa75ab..1ef8f642719 100644
--- a/gcc/dse.c
+++ b/gcc/dse.c
@@ -1532,7 +1532,12 @@ record_store (rtx body, bb_info_t bb_info)
 	      && known_subrange_p (offset, width,
 				   s_info->offset, s_info->width)
 	      && all_positions_needed_p (s_info, offset - s_info->offset,
-					 width))
+					 width)
+	      /* We can only remove the later store if the earlier aliases
+		 at least all accesses the later one.  */
+	      && (MEM_ALIAS_SET (mem) == MEM_ALIAS_SET (s_info->mem)
+		  || alias_set_subset_of (MEM_ALIAS_SET (mem),
+					  MEM_ALIAS_SET (s_info->mem))))
 	    {
 	      if (GET_MODE (mem) == BLKmode)
 		{
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 65bfe0fc440..92bbe451eb1 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2018-01-26  Richard Biener  <rguenther@suse.de>
+
+	PR rtl-optimization/84003
+	* g++.dg/torture/pr77745.C: Mark foo noinline to trigger
+	latent bug in DSE if NOINLINE is appropriately defined.
+	* g++.dg/torture/pr77745-2.C: New testcase including pr77745.C
+	and defining NOINLINE.
+
 2018-01-26  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* gcc.target/aarch64/advsimd-intrinsics/vld1x2.c: Make float64
diff --git a/gcc/testsuite/g++.dg/torture/pr77745-2.C b/gcc/testsuite/g++.dg/torture/pr77745-2.C
new file mode 100644
index 00000000000..7861089a817
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr77745-2.C
@@ -0,0 +1,4 @@
+// { dg-do run }
+
+#define NOINLINE __attribute__((noinline))
+#include "pr77745.C"
diff --git a/gcc/testsuite/g++.dg/torture/pr77745.C b/gcc/testsuite/g++.dg/torture/pr77745.C
index 59d86b5c501..6285bc14a43 100644
--- a/gcc/testsuite/g++.dg/torture/pr77745.C
+++ b/gcc/testsuite/g++.dg/torture/pr77745.C
@@ -1,8 +1,12 @@
 // { dg-do run }
 
+#ifndef NOINLINE
+#define NOINLINE /* */
+#endif
+
 inline void* operator new(__SIZE_TYPE__, void* __p) noexcept { return __p; }
 
-long foo(char *c1, char *c2)
+long NOINLINE foo(char *c1, char *c2)
 {
   long *p1 = new (c1) long;
   *p1 = 100;