From: Bernd Edlinger <bernd.edlinger@hotmail.de>
Date: Mon, 23 Jul 2018 13:23:51 +0000 (+0000)
Subject: re PR c/86617 (Volatile qualifier is ignored sometimes for unsigned char)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1544db9a61b6a441be68c5a6ba2504a6ccc2b956;p=gcc.git

re PR c/86617 (Volatile qualifier is ignored sometimes for unsigned char)

gcc:
2018-07-23  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        PR c/86617
        * genmatch.c (dt_operand::gen_match_op): Avoid folding volatile values.

testsuite:
2018-07-23  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        PR c/86617
        * gcc.dg/pr86617.c: New test.

From-SVN: r262933
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2cbe833dcfd..3f4283fd739 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2018-07-23  Bernd Edlinger  <bernd.edlinger@hotmail.de>
+
+	PR c/86617
+	* genmatch.c (dt_operand::gen_match_op): Avoid folding volatile values.
+
 2018-07-23  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	* gimple-fold.c (gimple_fold_builtin_printf): Don't create a not NUL
diff --git a/gcc/genmatch.c b/gcc/genmatch.c
index 5d6cf0b4d3a..5848722684b 100644
--- a/gcc/genmatch.c
+++ b/gcc/genmatch.c
@@ -2748,12 +2748,14 @@ dt_operand::gen_match_op (FILE *f, int indent, const char *opname, bool)
   char match_opname[20];
   match_dop->get_name (match_opname);
   if (value_match)
-    fprintf_indent (f, indent, "if (%s == %s || operand_equal_p (%s, %s, 0))\n",
-		    opname, match_opname, opname, match_opname);
+    fprintf_indent (f, indent, "if ((%s == %s && ! TREE_SIDE_EFFECTS (%s)) "
+		    "|| operand_equal_p (%s, %s, 0))\n",
+		    opname, match_opname, opname, opname, match_opname);
   else
-    fprintf_indent (f, indent, "if (%s == %s || (operand_equal_p (%s, %s, 0) "
+    fprintf_indent (f, indent, "if ((%s == %s && ! TREE_SIDE_EFFECTS (%s)) "
+		    "|| (operand_equal_p (%s, %s, 0) "
 		    "&& types_match (%s, %s)))\n",
-		    opname, match_opname, opname, match_opname,
+		    opname, match_opname, opname, opname, match_opname,
 		    opname, match_opname);
   fprintf_indent (f, indent + 2, "{\n");
   return 1;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b5e2a54e9b2..5e6b8eb87d1 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-07-23  Bernd Edlinger  <bernd.edlinger@hotmail.de>
+
+	PR c/86617
+	* gcc.dg/pr86617.c: New test.
+
 2018-07-23  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/86569
diff --git a/gcc/testsuite/gcc.dg/pr86617.c b/gcc/testsuite/gcc.dg/pr86617.c
new file mode 100644
index 00000000000..72135e205bd
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr86617.c
@@ -0,0 +1,11 @@
+/* { dg-options "-Os -fdump-rtl-final" } */
+
+volatile unsigned char u8;
+
+void test (void)
+{
+  u8 = u8 + u8;
+  u8 = u8 - u8;
+}
+
+/* { dg-final { scan-rtl-dump-times "mem/v" 6 "final" } } */