2009-06-22 Basile Starynkevitch <basile@starynkevitch.net>

	MELT branch merged with trunk r148777



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/melt-branch@148778 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 228 insertions, 24 deletions

diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 6cbec5de2bf..98955246aea 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -168,14 +168,9 @@ ptr_deref_may_alias_decl_p (tree ptr, tree decl)
 {
   struct ptr_info_def *pi;
 
-  /* ???  During SCCVN/PRE we can end up with *&x during valueizing
-     operands.  Likewise we can end up with dereferencing constant
-     pointers.  Just bail out in these cases for now.  */
-  if (TREE_CODE (ptr) == ADDR_EXPR
-      || TREE_CODE (ptr) == INTEGER_CST)
-    return true;
-
-  gcc_assert (TREE_CODE (ptr) == SSA_NAME
+  gcc_assert ((TREE_CODE (ptr) == SSA_NAME
+	       || TREE_CODE (ptr) == ADDR_EXPR
+	       || TREE_CODE (ptr) == INTEGER_CST)
 	      && (TREE_CODE (decl) == VAR_DECL
 		  || TREE_CODE (decl) == PARM_DECL
 		  || TREE_CODE (decl) == RESULT_DECL));
@@ -184,6 +179,29 @@ ptr_deref_may_alias_decl_p (tree ptr, tree decl)
   if (!may_be_aliased (decl))
     return false;
 
+  /* ADDR_EXPR pointers either just offset another pointer or directly
+     specify the pointed-to set.  */
+  if (TREE_CODE (ptr) == ADDR_EXPR)
+    {
+      tree base = get_base_address (TREE_OPERAND (ptr, 0));
+      if (base
+	  && INDIRECT_REF_P (base))
+	ptr = TREE_OPERAND (base, 0);
+      else if (base
+	       && SSA_VAR_P (base))
+	return operand_equal_p (base, decl, 0);
+      else if (base
+	       && CONSTANT_CLASS_P (base))
+	return false;
+      else
+	return true;
+    }
+
+  /* We can end up with dereferencing constant pointers.
+     Just bail out in this case.  */
+  if (TREE_CODE (ptr) == INTEGER_CST)
+    return true;
+
   /* If we do not have useful points-to information for this pointer
      we cannot disambiguate anything else.  */
   pi = SSA_NAME_PTR_INFO (ptr);
@@ -202,18 +220,46 @@ ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
 {
   struct ptr_info_def *pi1, *pi2;
 
-  /* ???  During SCCVN/PRE we can end up with *&x during valueizing
-     operands.  Likewise we can end up with dereferencing constant
-     pointers.  Just bail out in these cases for now.  */
-  if (TREE_CODE (ptr1) == ADDR_EXPR
-      || TREE_CODE (ptr1) == INTEGER_CST
-      || TREE_CODE (ptr2) == ADDR_EXPR
+  gcc_assert ((TREE_CODE (ptr1) == SSA_NAME
+	       || TREE_CODE (ptr1) == ADDR_EXPR
+	       || TREE_CODE (ptr1) == INTEGER_CST)
+	      && (TREE_CODE (ptr2) == SSA_NAME
+		  || TREE_CODE (ptr2) == ADDR_EXPR
+		  || TREE_CODE (ptr2) == INTEGER_CST));
+
+  /* ADDR_EXPR pointers either just offset another pointer or directly
+     specify the pointed-to set.  */
+  if (TREE_CODE (ptr1) == ADDR_EXPR)
+    {
+      tree base = get_base_address (TREE_OPERAND (ptr1, 0));
+      if (base
+	  && INDIRECT_REF_P (base))
+	ptr1 = TREE_OPERAND (base, 0);
+      else if (base
+	       && SSA_VAR_P (base))
+	return ptr_deref_may_alias_decl_p (ptr2, base);
+      else
+	return true;
+    }
+  if (TREE_CODE (ptr2) == ADDR_EXPR)
+    {
+      tree base = get_base_address (TREE_OPERAND (ptr2, 0));
+      if (base
+	  && INDIRECT_REF_P (base))
+	ptr2 = TREE_OPERAND (base, 0);
+      else if (base
+	       && SSA_VAR_P (base))
+	return ptr_deref_may_alias_decl_p (ptr1, base);
+      else
+	return true;
+    }
+
+  /* We can end up with dereferencing constant pointers.
+     Just bail out in this case.  */
+  if (TREE_CODE (ptr1) == INTEGER_CST
       || TREE_CODE (ptr2) == INTEGER_CST)
     return true;
 
-  gcc_assert (TREE_CODE (ptr1) == SSA_NAME
-	      && TREE_CODE (ptr2) == SSA_NAME);
-
   /* We may end up with two empty points-to solutions for two same pointers.
      In this case we still want to say both pointers alias, so shortcut
      that here.  */
@@ -232,6 +278,31 @@ ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
   return pt_solutions_intersect (&pi1->pt, &pi2->pt);
 }
 
+/* Return true if dereferencing PTR may alias *REF.
+   The caller is responsible for applying TBAA to see if PTR
+   may access *REF at all.  */
+
+static bool
+ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref)
+{
+  tree base = ao_ref_base (ref);
+
+  if (INDIRECT_REF_P (base))
+    return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0));
+  else if (SSA_VAR_P (base))
+    return ptr_deref_may_alias_decl_p (ptr, base);
+
+  return true;
+}
+
+static bool
+ptr_deref_may_alias_ref_p (tree ptr, tree ref)
+{
+  ao_ref r;
+  ao_ref_init (&r, ref);
+  return ptr_deref_may_alias_ref_p_1 (ptr, &r);
+}
+
 
 /* Dump alias information on FILE.  */
 
@@ -778,7 +849,7 @@ refs_output_dependent_p (tree store1, tree store2)
 static bool
 ref_maybe_used_by_call_p_1 (gimple call, tree ref)
 {
-  tree base;
+  tree base, callee;
   unsigned i;
   int flags = gimple_call_flags (call);
 
@@ -803,13 +874,64 @@ ref_maybe_used_by_call_p_1 (gimple call, tree ref)
       && !is_global_var (base))
     goto process_args;
 
+  callee = gimple_call_fndecl (call);
+
+  /* Handle those builtin functions explicitly that do not act as
+     escape points.  See tree-ssa-structalias.c:find_func_aliases
+     for the list of builtins we might need to handle here.  */
+  if (callee != NULL_TREE
+      && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
+    switch (DECL_FUNCTION_CODE (callee))
+      {
+	/* All the following functions clobber memory pointed to by
+	   their first argument.  */
+	case BUILT_IN_STRCPY:
+	case BUILT_IN_STRNCPY:
+	case BUILT_IN_BCOPY:
+	case BUILT_IN_MEMCPY:
+	case BUILT_IN_MEMMOVE:
+	case BUILT_IN_MEMPCPY:
+	case BUILT_IN_STPCPY:
+	case BUILT_IN_STPNCPY:
+	case BUILT_IN_STRCAT:
+	case BUILT_IN_STRNCAT:
+	  {
+	    tree src = gimple_call_arg (call, 1);
+	    return ptr_deref_may_alias_ref_p (src, ref);
+	  }
+	/* The following builtins do not read from memory.  */
+	case BUILT_IN_FREE:
+	case BUILT_IN_MEMSET:
+	case BUILT_IN_FREXP:
+	case BUILT_IN_FREXPF:
+	case BUILT_IN_FREXPL:
+	case BUILT_IN_GAMMA_R:
+	case BUILT_IN_GAMMAF_R:
+	case BUILT_IN_GAMMAL_R:
+	case BUILT_IN_LGAMMA_R:
+	case BUILT_IN_LGAMMAF_R:
+	case BUILT_IN_LGAMMAL_R:
+	case BUILT_IN_MODF:
+	case BUILT_IN_MODFF:
+	case BUILT_IN_MODFL:
+	case BUILT_IN_REMQUO:
+	case BUILT_IN_REMQUOF:
+	case BUILT_IN_REMQUOL:
+	case BUILT_IN_SINCOS:
+	case BUILT_IN_SINCOSF:
+	case BUILT_IN_SINCOSL:
+	  return false;
+
+	default:
+	  /* Fallthru to general call handling.  */;
+      }
+
   /* Check if base is a global static variable that is not read
      by the function.  */
   if (TREE_CODE (base) == VAR_DECL
       && TREE_STATIC (base)
       && !TREE_PUBLIC (base))
     {
-      tree callee = gimple_call_fndecl (call);
       bitmap not_read;
 
       if (callee != NULL_TREE
@@ -901,6 +1023,7 @@ static bool
 call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
 {
   tree base;
+  tree callee;
 
   /* If the call is pure or const it cannot clobber anything.  */
   if (gimple_call_flags (call)
@@ -926,18 +1049,99 @@ call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
 	  || !is_global_var (base)))
     return false;
 
+  callee = gimple_call_fndecl (call);
+
+  /* Handle those builtin functions explicitly that do not act as
+     escape points.  See tree-ssa-structalias.c:find_func_aliases
+     for the list of builtins we might need to handle here.  */
+  if (callee != NULL_TREE
+      && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
+    switch (DECL_FUNCTION_CODE (callee))
+      {
+	/* All the following functions clobber memory pointed to by
+	   their first argument.  */
+	case BUILT_IN_STRCPY:
+	case BUILT_IN_STRNCPY:
+	case BUILT_IN_BCOPY:
+	case BUILT_IN_MEMCPY:
+	case BUILT_IN_MEMMOVE:
+	case BUILT_IN_MEMPCPY:
+	case BUILT_IN_STPCPY:
+	case BUILT_IN_STPNCPY:
+	case BUILT_IN_STRCAT:
+	case BUILT_IN_STRNCAT:
+	  {
+	    tree dest = gimple_call_arg (call, 0);
+	    return ptr_deref_may_alias_ref_p_1 (dest, ref);
+	  }
+	/* Freeing memory kills the pointed-to memory.  More importantly
+	   the call has to serve as a barrier for moving loads and stores
+	   across it.  Same is true for memset.  */
+	case BUILT_IN_FREE:
+	case BUILT_IN_MEMSET:
+	  {
+	    tree ptr = gimple_call_arg (call, 0);
+	    return ptr_deref_may_alias_ref_p_1 (ptr, ref);
+	  }
+	case BUILT_IN_GAMMA_R:
+	case BUILT_IN_GAMMAF_R:
+	case BUILT_IN_GAMMAL_R:
+	case BUILT_IN_LGAMMA_R:
+	case BUILT_IN_LGAMMAF_R:
+	case BUILT_IN_LGAMMAL_R:
+	  {
+	    tree out = gimple_call_arg (call, 1);
+	    if (ptr_deref_may_alias_ref_p_1 (out, ref))
+	      return true;
+	    if (flag_errno_math)
+	      break;
+	    return false;
+	  }
+	case BUILT_IN_FREXP:
+	case BUILT_IN_FREXPF:
+	case BUILT_IN_FREXPL:
+	case BUILT_IN_MODF:
+	case BUILT_IN_MODFF:
+	case BUILT_IN_MODFL:
+	  {
+	    tree out = gimple_call_arg (call, 1);
+	    return ptr_deref_may_alias_ref_p_1 (out, ref);
+	  }
+	case BUILT_IN_REMQUO:
+	case BUILT_IN_REMQUOF:
+	case BUILT_IN_REMQUOL:
+	  {
+	    tree out = gimple_call_arg (call, 2);
+	    if (ptr_deref_may_alias_ref_p_1 (out, ref))
+	      return true;
+	    if (flag_errno_math)
+	      break;
+	    return false;
+	  }
+	case BUILT_IN_SINCOS:
+	case BUILT_IN_SINCOSF:
+	case BUILT_IN_SINCOSL:
+	  {
+	    tree sin = gimple_call_arg (call, 1);
+	    tree cos = gimple_call_arg (call, 2);
+	    return (ptr_deref_may_alias_ref_p_1 (sin, ref)
+		    || ptr_deref_may_alias_ref_p_1 (cos, ref));
+	  }
+	default:
+	  /* Fallthru to general call handling.  */;
+      }
+
   /* Check if base is a global static variable that is not written
      by the function.  */
-  if (TREE_CODE (base) == VAR_DECL
+  if (callee != NULL_TREE
+      && TREE_CODE (base) == VAR_DECL
       && TREE_STATIC (base)
       && !TREE_PUBLIC (base))
     {
-      tree callee = gimple_call_fndecl (call);
       bitmap not_written;
 
-      if (callee != NULL_TREE
-	  && (not_written
-	        = ipa_reference_get_not_written_global (cgraph_node (callee)))
+      if ((not_written
+	     = ipa_reference_get_not_written_global (cgraph_node (callee)))
 	  && bitmap_bit_p (not_written, DECL_UID (base)))
 	return false;
     }