From: Richard Sandiford <richard.sandiford@linaro.org>
Date: Wed, 29 Jun 2011 09:42:42 +0000 (+0000)
Subject: re PR middle-end/49545 (New C++ test failures)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=73f6eabc3ae4de22a83135f03f8c8688623661a1;p=gcc.git

re PR middle-end/49545 (New C++ test failures)

gcc/
	PR tree-optimization/49545
	* builtins.c (get_object_alignment_1): Update function comment.
	Do not use DECL_ALIGN for functions, but test
	TARGET_PTRMEMFUNC_VBIT_LOCATION instead.
	* fold-const.c (get_pointer_modulus_and_residue): Don't check
	for functions here.
	* tree-ssa-ccp.c (get_value_from_alignment): Likewise.

gcc/testsuite/
	* gcc.dg/torture/pr49169.c: Restrict to ARM and MIPS targets.

From-SVN: r175627
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 91c23f2a20c..0a87e3c6921 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2011-06-29  Richard Sandiford  <richard.sandiford@linaro.org>
+
+	PR tree-optimization/49545
+	* builtins.c (get_object_alignment_1): Update function comment.
+	Do not use DECL_ALIGN for functions, but test
+	TARGET_PTRMEMFUNC_VBIT_LOCATION instead.
+	* fold-const.c (get_pointer_modulus_and_residue): Don't check
+	for functions here.
+	* tree-ssa-ccp.c (get_value_from_alignment): Likewise.
+
 2011-06-29  Jakub Jelinek  <jakub@redhat.com>
 
 	PR debug/49567
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 0747e04a3af..1ee8cf80001 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -264,8 +264,15 @@ called_as_built_in (tree node)
   return is_builtin_name (name);
 }
 
-/* Return the alignment in bits of EXP, an object.
-   Don't return more than MAX_ALIGN no matter what.  */
+/* Compute values M and N such that M divides (address of EXP - N) and
+   such that N < M.  Store N in *BITPOSP and return M.
+
+   Note that the address (and thus the alignment) computed here is based
+   on the address to which a symbol resolves, whereas DECL_ALIGN is based
+   on the address at which an object is actually located.  These two
+   addresses are not always the same.  For example, on ARM targets,
+   the address &foo of a Thumb function foo() has the lowest bit set,
+   whereas foo() itself starts on an even address.  */
 
 unsigned int
 get_object_alignment_1 (tree exp, unsigned HOST_WIDE_INT *bitposp)
@@ -287,7 +294,21 @@ get_object_alignment_1 (tree exp, unsigned HOST_WIDE_INT *bitposp)
     exp = DECL_INITIAL (exp);
   if (DECL_P (exp)
       && TREE_CODE (exp) != LABEL_DECL)
-    align = DECL_ALIGN (exp);
+    {
+      if (TREE_CODE (exp) == FUNCTION_DECL)
+	{
+	  /* Function addresses can encode extra information besides their
+	     alignment.  However, if TARGET_PTRMEMFUNC_VBIT_LOCATION
+	     allows the low bit to be used as a virtual bit, we know
+	     that the address itself must be 2-byte aligned.  */
+	  if (TARGET_PTRMEMFUNC_VBIT_LOCATION == ptrmemfunc_vbit_in_pfn)
+	    align = 2 * BITS_PER_UNIT;
+	  else
+	    align = BITS_PER_UNIT;
+	}
+      else
+	align = DECL_ALIGN (exp);
+    }
   else if (CONSTANT_CLASS_P (exp))
     {
       align = TYPE_ALIGN (TREE_TYPE (exp));
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 9428c11e4ac..e48aae9f4ce 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -9216,8 +9216,7 @@ get_pointer_modulus_and_residue (tree expr, unsigned HOST_WIDE_INT *residue,
   *residue = 0;
 
   code = TREE_CODE (expr);
-  if (code == ADDR_EXPR
-      && TREE_CODE (TREE_OPERAND (expr, 0)) != FUNCTION_DECL)
+  if (code == ADDR_EXPR)
     {
       unsigned int bitalign;
       bitalign = get_object_alignment_1 (TREE_OPERAND (expr, 0), residue);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f0b9eb10377..ee7274790fd 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2011-06-29  Richard Sandiford  <richard.sandiford@linaro.org>
+
+	* gcc.dg/torture/pr49169.c: Restrict to ARM and MIPS targets.
+
 2011-06-29  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* gcc.dg/inline_1.c: Remove dg-excess-errors.
diff --git a/gcc/testsuite/gcc.dg/torture/pr49169.c b/gcc/testsuite/gcc.dg/torture/pr49169.c
index 721b2ac6435..c7800bb7536 100644
--- a/gcc/testsuite/gcc.dg/torture/pr49169.c
+++ b/gcc/testsuite/gcc.dg/torture/pr49169.c
@@ -1,3 +1,5 @@
+/* { dg-do compile { target { arm*-*-* || mips*-*-* } } } */
+
 #include <stdlib.h>
 #include <stdint.h>
 
diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c
index 78724de286b..94a09e0bbc9 100644
--- a/gcc/tree-ssa-ccp.c
+++ b/gcc/tree-ssa-ccp.c
@@ -520,10 +520,6 @@ get_value_from_alignment (tree expr)
     val = bit_value_binop (PLUS_EXPR, TREE_TYPE (expr),
 			   TREE_OPERAND (base, 0), TREE_OPERAND (base, 1));
   else if (base
-	   /* ???  While function decls have DECL_ALIGN their addresses
-	      may encode extra information in the lower bits on some
-	      targets (PR47239).  Simply punt for function decls for now.  */
-	   && TREE_CODE (base) != FUNCTION_DECL
 	   && ((align = get_object_alignment (base, BIGGEST_ALIGNMENT))
 		> BITS_PER_UNIT))
     {