re PR target/50305 (Inline asm reload failure when building Linux kernel)

	gcc/
	PR target/50305
	* config/arm/arm.c (arm_legitimize_reload_address): Recognize
	output of a previous pass through legitimize_reload_address.
	Do not attempt to optimize addresses if the base register is
	equivalent to a constant.

	gcc/testsuite/
	PR target/50305
	* gcc.target/arm/pr50305.c: New test.

From-SVN: r179603

4 files changed, 90 insertions, 0 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f8d41cc..8c54eaf 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2011-10-06  Ulrich Weigand  <ulrich.weigand@linaro.org>
+
+	PR target/50305
+	* config/arm/arm.c (arm_legitimize_reload_address): Recognize
+	output of a previous pass through legitimize_reload_address.
+	Do not attempt to optimize addresses if the base register is
+	equivalent to a constant.
+
 2011-10-06  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>
 
 	* function.c (thread_prologue_and_epilogue_insns): Mark
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 5161439..2feac6f 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -6550,9 +6550,26 @@ arm_legitimize_reload_address (rtx *p,
 			       int opnum, int type,
 			       int ind_levels ATTRIBUTE_UNUSED)
 {
+  /* We must recognize output that we have already generated ourselves.  */
+  if (GET_CODE (*p) == PLUS
+      && GET_CODE (XEXP (*p, 0)) == PLUS
+      && GET_CODE (XEXP (XEXP (*p, 0), 0)) == REG
+      && GET_CODE (XEXP (XEXP (*p, 0), 1)) == CONST_INT
+      && GET_CODE (XEXP (*p, 1)) == CONST_INT)
+    {
+      push_reload (XEXP (*p, 0), NULL_RTX, &XEXP (*p, 0), NULL,
+		   MODE_BASE_REG_CLASS (mode), GET_MODE (*p),
+		   VOIDmode, 0, 0, opnum, (enum reload_type) type);
+      return true;
+    }
+
   if (GET_CODE (*p) == PLUS
       && GET_CODE (XEXP (*p, 0)) == REG
       && ARM_REGNO_OK_FOR_BASE_P (REGNO (XEXP (*p, 0)))
+      /* If the base register is equivalent to a constant, let the generic
+	 code handle it.  Otherwise we will run into problems if a future
+	 reload pass decides to rematerialize the constant.  */
+      && !reg_equiv_constant (ORIGINAL_REGNO (XEXP (*p, 0)))
       && GET_CODE (XEXP (*p, 1)) == CONST_INT)
     {
       HOST_WIDE_INT val = INTVAL (XEXP (*p, 1));
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 458bacb..27f7746 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-10-06  Ulrich Weigand  <ulrich.weigand@linaro.org>
+
+	PR target/50305
+	* gcc.target/arm/pr50305.c: New test.
+
 2011-10-06  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/38884
diff --git a/gcc/testsuite/gcc.target/arm/pr50305.c b/gcc/testsuite/gcc.target/arm/pr50305.c
new file mode 100644
index 0000000..2f6ad5c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr50305.c
@@ -0,0 +1,60 @@
+/* { dg-do compile } */
+/* { dg-skip-if "incompatible options" { arm*-*-* } { "-march=*" } { "-march=armv7-a" } } */
+/* { dg-options "-O2 -fno-omit-frame-pointer -marm -march=armv7-a -mfpu=vfp3" } */
+
+struct event {
+ unsigned long long id;
+ unsigned int flag;
+};
+
+void dummy(void)
+{
+  /* This is here to ensure that the offset of perf_event_id below
+     relative to the LANCHOR symbol exceeds the allowed displacement.  */
+  static int __warned[300];
+ __warned[0] = 1;
+}
+
+extern void *kmem_cache_alloc_trace (void *cachep);
+extern void *cs_cachep;
+extern int nr_cpu_ids;
+
+struct event *
+event_alloc (int cpu)
+{
+ static unsigned long long __attribute__((aligned(8))) perf_event_id;
+ struct event *event;
+ unsigned long long result;
+ unsigned long tmp;
+
+ if (cpu >= nr_cpu_ids)
+  return 0;
+
+ event = kmem_cache_alloc_trace (cs_cachep);
+
+ __asm__ __volatile__ ("dmb" : : : "memory");
+
+ __asm__ __volatile__("@ atomic64_add_return\n"
+"1:	ldrexd	%0, %H0, [%3]\n"
+"	adds	%0, %0, %4\n"
+"	adc	%H0, %H0, %H4\n"
+"	strexd	%1, %0, %H0, [%3]\n"
+"	teq	%1, #0\n"
+"	bne	1b"
+ : "=&r" (result), "=&r" (tmp), "+Qo" (perf_event_id)
+ : "r" (&perf_event_id), "r" (1LL)
+ : "cc");
+
+ __asm__ __volatile__ ("dmb" : : : "memory");
+
+ event->id = result;
+
+ if (cpu)
+  event->flag = 1;
+
+ for (cpu = 0; cpu < nr_cpu_ids; cpu++)
+   kmem_cache_alloc_trace (cs_cachep);
+
+ return event;
+}
+