Workaround PR68256 on AArch64

> This is causing a bootstrap comparison failure in gcc/go/gogo.o.

I've had a look at this and the trigger is the
aarch64_use_constant_blocks_p change which appears to be causing a
bootstrap comparison failure because of differences to offsets when
built with debug and without debug. I don't think the problem is
specifically in the backend but this needs some careful
investigation. For now, in the interest of go bootstraps continuing on
trunk - I'm proposing a patch that partially rolls back the change in
aarch64_use_constant_blocks_p and am still looking into the issue but
it will take me some more time to get to the bottom of the issue.

Bootstrapped on aarch64-none-linux-gnu including (c,c++ and go) -
testing finished ok.

2015-11-10  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>

	PR bootstrap/68256
	* config/aarch64/aarch64.c (aarch64_use_constant_blocks_p):
	Return false.

From-SVN: r230085

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 32c31559f7addc225354e3209effa8fd1b20b71d..577267a8f62023ff76f459dff34269d0c10bf687 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2015-11-10  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
+
+       PR bootstrap/68256
+       * config/aarch64/aarch64.c (aarch64_use_constant_blocks_p):
+       Return false.
+
 2015-11-09  Eric Botcazou  <ebotcazou@adacore.com>
 
        PR target/57845

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index a4d824b2151570110ec32e3f8ca89b30bf7384b5..7d6dfc342b85d7967292454c2512865951452f5b 100644 (file)
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -5244,9 +5244,11 @@ aarch64_can_use_per_function_literal_pools_p (void)
 static bool
 aarch64_use_blocks_for_constant_p (machine_mode, const_rtx)
 {
-  /* We can't use blocks for constants when we're using a per-function
-     constant pool.  */
-  return !aarch64_can_use_per_function_literal_pools_p ();
+  /* Fixme:: In an ideal world this would work similar
+     to the logic in aarch64_select_rtx_section but this
+     breaks bootstrap in gcc go.  For now we workaround
+     this by returning false here.  */
+  return false;
 }
 
 /* Select appropriate section for constants depending