[PATCH 01/10] [ARC][LRA] Use TARGET_CANNOT_SUBSTITUTE_MEM_EQUIV.

[Claudiu Zissulescu <Claudiu dot Zissulescu at synopsys dot com>]

From: Claudiu Zissulescu <claziss@gmail.com>

Sometimes the memory equivalent is not valid due to a large offset.
For example replacing the ap register with its fp/sp-equivalent during
LRA step. To solve this we introduced TARGET_CANNOT_SUBSTITUTE_MEM_EQUIV.

gcc/
2017-08-08  Claudiu Zissulescu  <claziss@synopsys.com>

	* config/arc/arc.c (arc_cannot_substitute_mem_equiv_p): New function.
	(TARGET_CANNOT_SUBSTITUTE_MEM_EQUIV_P): Define.

gcc/testsuite
2017-08-08  Claudiu Zissulescu  <claziss@synopsys.com>

	* gcc.target/arc/lra-1.c: New test.
---
 gcc/config/arc/arc.c                 | 12 ++++++++++++
 gcc/testsuite/gcc.target/arc/lra-1.c | 17 +++++++++++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/arc/lra-1.c

diff --git a/gcc/config/arc/arc.c b/gcc/config/arc/arc.c
index dd922a6..25f123c 100644
--- a/gcc/config/arc/arc.c
+++ b/gcc/config/arc/arc.c
@@ -11352,12 +11352,24 @@ arc_use_anchors_for_symbol_p (const_rtx symbol)
   return default_use_anchors_for_symbol_p (symbol);
 }
 
+/* Return true if SUBST can't safely replace its equivalent during RA.  */
+static bool
+arc_cannot_substitute_mem_equiv_p (rtx)
+{
+  /* If SUBST is mem[base+index], the address may not fit iSA, 
+     thus return true. */
+  return true;
+}
+
 #undef TARGET_USE_ANCHORS_FOR_SYMBOL_P
 #define TARGET_USE_ANCHORS_FOR_SYMBOL_P arc_use_anchors_for_symbol_p
 
 #undef TARGET_CONSTANT_ALIGNMENT
 #define TARGET_CONSTANT_ALIGNMENT constant_alignment_word_strings
 
+#undef TARGET_CANNOT_SUBSTITUTE_MEM_EQUIV_P
+#define TARGET_CANNOT_SUBSTITUTE_MEM_EQUIV_P arc_cannot_substitute_mem_equiv_p
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 #include "gt-arc.h"
diff --git a/gcc/testsuite/gcc.target/arc/lra-1.c b/gcc/testsuite/gcc.target/arc/lra-1.c
new file mode 100644
index 0000000..27336d1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arc/lra-1.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-Os -w -mlra" } */
+
+/* ap is replaced with an address like base+offset by lra,
+   where offset is larger than s9, resulting into an ICE.  */
+
+typedef struct { char a[500] } b;
+c;
+struct d {
+  short e;
+  b f
+} g(int h, int i, int j, int k, char l, int m, int n, char *p) {
+again:;
+  struct d o;
+  *p = c = ({ q(o); });
+  goto again;
+}
-- 
1.9.1