re PR target/87033 (The compiler does not generate the LWAX instruction)

[gcc]
2018-08-20  Michael Meissner  <meissner@linux.ibm.com>

	PR target/87033
	* config/rs6000/rs6000.md (extendsi<mode>2): Change constraints
	from 'Y' to 'YZ' to enable the LWAX instruction to be generated
	for indexed loads.

[gcc/testsuite]
2018-08-20  Michael Meissner  <meissner@linux.ibm.com>

	PR target/87033
	* gcc.target/powerpc/pr87033.c: New test.

From-SVN: r263678

gcc/ChangeLog

+2018-08-20  Michael Meissner  <meissner@linux.ibm.com>
+
+	PR target/87033
+	* config/rs6000/rs6000.md (extendsi<mode>2): Change constraints
+	from 'Y' to 'YZ' to enable the LWAX instruction to be generated
+	for indexed loads.
+
 2018-08-20  Nathan Sidwell  <nathan@acm.org>
 	    Jeff Law <law@redhat.com>
 

gcc/config/rs6000/rs6000.md

@@ -988,7 +988,7 @@
 		     "=r, r,   wl,    wu,    wj,    wK,     wH,    wr")
 
 	(sign_extend:EXTSI (match_operand:SI 1 "lwa_operand"
-		     "Y,  r,   Z,     Z,     r,     wK,     wH,    ?wIwH")))]
+		     "YZ, r,   Z,     Z,     r,     wK,     wH,    ?wIwH")))]
   ""
   "@
    lwa%U1%X1 %0,%1

gcc/testsuite/ChangeLog

+2018-08-20  Michael Meissner  <meissner@linux.ibm.com>
+
+	PR target/87033
+	* gcc.target/powerpc/pr87033.c: New test.
+
 2018-08-20  Martin Sebor  <msebor@redhat.com>
 
 	PR tree-optimization/87034

gcc/testsuite/gcc.target/powerpc/pr87033.c

+/* { dg-do compile { target { powerpc*-*-* && lp64 } } } */
+/* { dg-options "-O2" } */
+
+/* Insure that a LWAX is generated instead of ADD + LWA.  LP64 is needed
+   because the LWA and LWAX instructions are only available in 64-bit mode.  */
+long func (int *p, unsigned long n)
+{
+  return p[n];
+}
+
+/* { dg-final { scan-assembler     {\mlwax\M} } } */
+/* { dg-final { scan-assembler-not {\mlwa\M}  } } */