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[Patch][google/gcc-4_8] Backport r198101 (fix for PR56847) into google/gcc-4_8
- From: Han Shen(ææ) <shenhan at google dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: Dehao Chen <dehao at google dot com>
- Date: Wed, 24 Apr 2013 17:49:15 -0700
- Subject: [Patch][google/gcc-4_8] Backport r198101 (fix for PR56847) into google/gcc-4_8
Hi, this patch back port trunk@198101 to fix PR rtl-optimization/56847.
Passed bootstrap and regression test.
Ok for branch google/gcc-4_8?
2013-04-19 Vladimir Makarov <vmakarov@redhat.com>
PR rtl-optimization/56847
* lra-constraints.c (process_alt_operands): Discourage alternative
with non-matche doffsettable memory constraint fro memory with
known offset.
diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index e3b4add..9e4924c 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -1978,8 +1978,15 @@ process_alt_operands (int only_alternative)
(op, this_alternative) == NO_REGS))))
reject += LRA_MAX_REJECT;
- if (! ((const_to_mem && constmemok)
- || (MEM_P (op) && offmemok)))
+ if (MEM_P (op) && offmemok)
+ {
+ /* If we know offset and this non-offsetable memory,
+ something wrong with this memory and it is better
+ to try other memory possibilities. */
+ if (MEM_OFFSET_KNOWN_P (op))
+ reject += LRA_MAX_REJECT;
+ }
+ else if (! (const_to_mem && constmemok))
{
/* We prefer to reload pseudos over reloading other
things, since such reloads may be able to be
diff --git a/gcc/testsuite/gcc.dg/pr56847.c b/gcc/testsuite/gcc.dg/pr56847.c
new file mode 100644
index 0000000..b94aae1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr56847.c
@@ -0,0 +1,12 @@
+/* PR rtl-optimization/56847 */
+/* { dg-do compile { target pie } } */
+/* { dg-options "-O2 -fpie" } */
+
+struct S { long int a, b; } e;
+__thread struct S s;
+
+void
+foo (void)
+{
+ s = e;
+}
H.