rs6000-builtin.def: (LVSL...

[gcc]

2019-09-26  Will Schmidt <will_schmidt@vnet.ibm.com>
	* config/rs6000/rs6000-builtin.def: (LVSL, LVSR, LVEBX, LVEHX,
	LVEWX, LVXL, LVXL_V2DF, LVXL_V2DI, LVXL_V4SF, LVXL_V4SI, LVXL_V8HI,
	LVXL_V16QI, LVX, LVX_V1TI, LVX_V2DF, LVX_V2DI, LVX_V4SF, LVX_V4SI,
	LVX_V8HI, LVX_V16QI, LVLX, LVLXL, LVRX, LVRXL, LXSDX, LXVD2X_V1TI,
	LXVD2X_V2DF, LXVD2X_V2DI, LXVDSX, LXVW4X_V4SF, LXVW4X_V4SI,
	LXVW4X_V8HI, LXVW4X_V16QI, LD_ELEMREV_V1TI, LD_ELEMREV_V2DF,
	LD_ELEMREV_V2DI, LD_ELEMREV_V4SF, LD_ELEMREV_V4SI, LD_ELEMREV_V8HI,
	LD_ELEMREV_V16QI): Use the PURE attribute.

[testsuite]

2019-09-26  Will Schmidt <will_schmidt@vnet.ibm.com>
	* gcc.target/powerpc/pure-builtin-redundant-load.c:  New.

From-SVN: r276163

gcc/testsuite/gcc.target/powerpc/pure-builtin-redundant-load.c

+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_vsx_ok } */
+/* { dg-options "-O2 -fdump-tree-fre-all -mvsx" } */
+
+/* Verify we remove a redundant load that occurs both before and after
+we call a vector load builtin.
+This testcase is introduced as we updated a number of our vector load
+built-ins with the attribute of PURE instead of MEM, to indicate that
+those builtins only read from memory, versus reading from and writing
+to the same.
+This means we can identify the redundant load instructions in an earlier
+pass, and optimize them away.  */
+
+#include <altivec.h>
+
+vector signed short load_data;
+
+vector signed short foo()
+{
+	vector signed short r11,r12,r13;
+	r11 = load_data;
+	r12 = vec_xl (0, &load_data[0]);
+	r13 = load_data;
+	return (r11 + r12 + r13);
+}
+
+vector signed short biz()
+{
+	vector signed short r21,r22,r23;
+	r21 = load_data;
+	r22 = vec_lvehx (0, &load_data[0]);
+	r23 = load_data;
+	return (r21 + r22 + r23);
+}
+
+vector signed short bar()
+{
+	vector signed short r31,r32,r33;
+	r31 = load_data;
+	r32 = vec_lvx (0, &load_data[0]);
+	r33 = load_data;
+	return (r31 + r32 + r33);
+}
+
+/* { dg-final { scan-tree-dump-times "Removing dead stmt r13_. = load_data;" 1 "fre1" } } */
+/* { dg-final { scan-tree-dump-times "Removing dead stmt r23_. = load_data;" 1 "fre1" } } */
+/* { dg-final { scan-tree-dump-times "Removing dead stmt r33_. = load_data;" 1 "fre1" } } */