From: Vladimir Makarov <vmakarov@redhat.com>
Date: Fri, 7 Apr 2017 16:01:50 +0000 (+0000)
Subject: re PR rtl-optimization/70478 ([LRA] S/390: Performance regression - superfluous stack... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=057da7af80d2fca356032c22efefcaf50d04da8b;p=gcc.git

re PR rtl-optimization/70478 ([LRA] S/390: Performance regression - superfluous stack frame)

2017-04-07  Vladimir Makarov  <vmakarov@redhat.com>

	PR rtl-optimization/70478
	* lra-constraints.c (process_alt_operands): Disfavor alternative
	insn memory operands.

2017-04-07  Vladimir Makarov  <vmakarov@redhat.com>

	PR rtl-optimization/70478
	* gcc.target/s390/pr70478.c: New.

From-SVN: r246764
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d68f161ca17..437c99dea47 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-04-07  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/70478
+	* lra-constraints.c (process_alt_operands): Disfavor alternative
+	insn memory operands.
+
 2017-04-07  Jeff Law  <law@redhat.com>
 
 	* config/iq2000/iq2000.c (final_prescan_insn): Do not separate a
diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index 4d986249a6f..9440205b66b 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -2685,6 +2685,21 @@ process_alt_operands (int only_alternative)
 		    }
 		}
 
+	      /* When we use memory operand, the insn should read the
+		 value from memory and even if we just wrote a value
+		 into the memory it is costly in comparison with an
+		 insn alternative which does not use memory
+		 (e.g. register or immediate operand).  */
+	      if (no_regs_p && offmemok)
+		{
+		  if (lra_dump_file != NULL)
+		    fprintf
+		      (lra_dump_file,
+		       "            Using memory insn operand %d: reject+=3\n",
+		       nop);
+		  reject += 3;
+		}
+	      
 #ifdef SECONDARY_MEMORY_NEEDED
 	      /* If reload requires moving value through secondary
 		 memory, it will need one more insn at least.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8b5a5806ea0..94fe5a04af3 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-04-07  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/70478
+	* gcc.target/s390/pr70478.c: New.
+
 2017-04-07  Martin Liska  <mliska@suse.cz>
 
 	PR target/79889
diff --git a/gcc/testsuite/gcc.target/s390/pr70478.c b/gcc/testsuite/gcc.target/s390/pr70478.c
new file mode 100644
index 00000000000..a1f135c2b56
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/pr70478.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-w -O3 -march=z9-109" } */
+/* { dg-final { scan-assembler-not "stg" } } */
+
+void foo(unsigned int *a, unsigned char *b)
+{
+  *a &= *b;
+}