From: Richard Henderson <rth@redhat.com>
Date: Fri, 5 Apr 2002 03:20:17 +0000 (-0800)
Subject: re PR rtl-optimization/6165 ([i686] stack frame freed too early)
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=638738b4440de464b5dfcc892d636f9bb0cce9f9;p=thirdparty%2Fgcc.git

re PR rtl-optimization/6165 ([i686] stack frame freed too early)

        PR opt/6165
        * alias.c (true_dependence): Force (mem:blk (scratch)) to conflict.
        (write_dependence_p): Likewise.

From-SVN: r51894
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1a7d5d09e332..91d20ccae867 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2002-04-04  Richard Henderson  <rth@redhat.com>
+
+	PR opt/6165
+	* alias.c (true_dependence): Force (mem:blk (scratch)) to conflict.
+	(write_dependence_p): Likewise.
+
 2002-04-04  David S. Miller  <davem@redhat.com>
 
 	* calls.c (store_one_arg): If ECF_SIBCALL, use tail_call_reg.
diff --git a/gcc/alias.c b/gcc/alias.c
index 060d1a5e076d..2725bd1bd8ed 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -1734,6 +1734,13 @@ true_dependence (mem, mem_mode, x, varies)
   if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
     return 1;
 
+  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+     This is used in epilogue deallocation functions.  */
+  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+    return 1;
+  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
+    return 1;
+
   if (DIFFERENT_ALIAS_SETS_P (x, mem))
     return 0;
 
@@ -1805,6 +1812,13 @@ write_dependence_p (mem, x, writep)
   if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
     return 1;
 
+  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+     This is used in epilogue deallocation functions.  */
+  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+    return 1;
+  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
+    return 1;
+
   if (DIFFERENT_ALIAS_SETS_P (x, mem))
     return 0;
 
diff --git a/gcc/flow.c b/gcc/flow.c
index 71a685e7b829..520303b839d4 100644
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -3948,7 +3948,7 @@ init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
      used later in the block are dead.  So make a pass over the block
      recording any such that are made and show them dead at the end.  We do
      a very conservative and simple job here.  */
-  if (optimize
+  if (0 && optimize
       && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
 	    && (TYPE_RETURNS_STACK_DEPRESSED
 		(TREE_TYPE (current_function_decl))))