From: Peter Bergner <bergner@vnet.ibm.com>
Date: Mon, 11 Jun 2018 18:25:37 +0000 (-0500)
Subject: backport: re PR target/85755 (PowerPC Gcc's -mupdate produces inefficient code on... 
X-Git-Tag: releases/gcc-7.4.0~409
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4e719bb23916643d12c4229a0949b24edbb54778;p=thirdparty%2Fgcc.git

backport: re PR target/85755 (PowerPC Gcc's -mupdate produces inefficient code on power8/power9 machines)

gcc/
	Backport from mainline
	2018-06-08  Peter Bergner  <bergner@vnet.ibm.com>

	PR target/85755
	* config/rs6000/rs6000.c (mem_operand_gpr): Enable PRE_INC and PRE_DEC
	addresses.

gcc/testsuite/
	Backport from mainline
	2018-06-08  Peter Bergner  <bergner@vnet.ibm.com>

	PR target/85755
	* gcc.target/powerpc/pr85755.c: New test.

From-SVN: r261442
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2dd1ec985e85..61eda2f22e20 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2018-06-11  Peter Bergner  <bergner@vnet.ibm.com>
+
+	Backport from mainline
+	2018-06-08  Peter Bergner  <bergner@vnet.ibm.com>
+
+	PR target/85755
+	* config/rs6000/rs6000.c (mem_operand_gpr): Enable PRE_INC and PRE_DEC
+	addresses.
+
 2018-06-07  Peter Bergner  <bergner@vnet.ibm.com>
 
 	Backport from mainline
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 75eab0375afc..01ae6ad8787c 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -8565,6 +8565,13 @@ mem_operand_gpr (rtx op, machine_mode mode)
   int extra;
   rtx addr = XEXP (op, 0);
 
+  /* PR85755: Allow PRE_INC and PRE_DEC addresses.  */
+  if (TARGET_UPDATE
+      && (GET_CODE (addr) == PRE_INC || GET_CODE (addr) == PRE_DEC)
+      && mode_supports_pre_incdec_p (mode)
+      && legitimate_indirect_address_p (XEXP (addr, 0), false))
+    return true;
+
   /* Don't allow non-offsettable addresses.  See PRs 83969 and 84279.  */
   if (!rs6000_offsettable_memref_p (op, mode, false))
     return false;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c31736667041..7909bf580547 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2018-06-11  Peter Bergner  <bergner@vnet.ibm.com>
+
+	Backport from mainline
+	2018-06-08  Peter Bergner  <bergner@vnet.ibm.com>
+
+	PR target/85755
+	* gcc.target/powerpc/pr85755.c: New test.
+
 2018-06-09  Steven G. Kargl  <kargl@gcc.gnu.org>
 
 	PR fortran/38351
diff --git a/gcc/testsuite/gcc.target/powerpc/pr85755.c b/gcc/testsuite/gcc.target/powerpc/pr85755.c
new file mode 100644
index 000000000000..2d8741d639ed
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr85755.c
@@ -0,0 +1,22 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-options "-O1" } */
+
+void
+preinc (long *q, long n)
+{
+  long i;
+  for (i = 0; i < n; i++)
+    q[i] = i;
+}
+
+void
+predec (long *q, long n)
+{
+  long i;
+  for (i = n; i >= 0; i--)
+    q[i] = i;
+}
+
+/* { dg-final { scan-assembler-times {\mstwu\M} 2 { target ilp32 } } } */
+/* { dg-final { scan-assembler-times {\mstdu\M} 2 { target lp64 } } } */
+/* { dg-final { scan-assembler-not {\mstfdu\M} } } */