Re: [PATCH] Fix PR 91605

[Bernd Edlinger <bernd dot edlinger at hotmail dot de>]

On 9/2/19 9:50 AM, Richard Biener wrote:
> On Sun, 1 Sep 2019, Bernd Edlinger wrote:
> 
>> Hi,
>>
>> this fixes an oversight in r274986.
>> We need to avoid using movmisalign on DECL_P which are not in memory,
>> similar to the !mem_ref_refers_to_non_mem_p which unfortunately can't
>> handle DECL_P.
>>
> 
> But
> 
> -      && (DECL_P (to) || !mem_ref_refers_to_non_mem_p (to))
> +      && (DECL_P (to) ? MEM_P (DECL_RTL (to))
> +                     : !mem_ref_refers_to_non_mem_p (to))
> 
> and in mem_ref_refers_to_non_mem_p we do
> 
>   if (!DECL_RTL_SET_P (base))
>     return nortl;
> 
>   return (!MEM_P (DECL_RTL (base)));
> 
> so when !DECL_RTL_SET_P (t) we can go full speed ahead?  That said,
> can we refactor addr_expr_of_non_mem_decl_p_1 to put
> 

Ah, I was not aware that DECL_RTL has a side-effect if !DECL_RTL_SET_P.


>   if (TREE_CODE (addr) != ADDR_EXPR)
>     return false;
> 
>   tree base = TREE_OPERAND (addr, 0);
> 
> into the single caller and re-use it then also for the DECL_P case?
> 

Yes, that is probably better then.

So how about this?
Is it OK?


Thanks
Bernd.

2019-09-01  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	PR middle-end/91605
	* expr.c (addr_expr_of_non_mem_decl_p_1): Refactor into...
	(non_mem_decl_p): ...this.
	(mem_ref_refers_to_non_mem_p): Handle DECL_P as well ase MEM_REF.
	(expand_assignment): Call mem_ref_referes_to_non_mem_p
	unconditionally as before.

testsuite:
2019-09-01  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	PR middle-end/91605
	* g++.target/i386/pr91605.C: New test.

Index: gcc/expr.c
===================================================================
--- gcc/expr.c	(revision 275279)
+++ gcc/expr.c	(working copy)
@@ -4942,18 +4942,13 @@ get_bit_range (poly_uint64_pod *bitstart, poly_uin
   *bitend = *bitstart + tree_to_poly_uint64 (DECL_SIZE (repr)) - 1;
 }
 
-/* Returns true if ADDR is an ADDR_EXPR of a DECL that does not reside
-   in memory and has non-BLKmode.  DECL_RTL must not be a MEM; if
-   DECL_RTL was not set yet, return NORTL.  */
+/* Returns true if BASE is a DECL that does not reside in memory and
+   has non-BLKmode.  DECL_RTL must not be a MEM; if
+   DECL_RTL was not set yet, return false.  */
 
 static inline bool
-addr_expr_of_non_mem_decl_p_1 (tree addr, bool nortl)
+non_mem_decl_p (tree base)
 {
-  if (TREE_CODE (addr) != ADDR_EXPR)
-    return false;
-
-  tree base = TREE_OPERAND (addr, 0);
-
   if (!DECL_P (base)
       || TREE_ADDRESSABLE (base)
       || DECL_MODE (base) == BLKmode)
@@ -4960,19 +4955,33 @@ static inline bool
     return false;
 
   if (!DECL_RTL_SET_P (base))
-    return nortl;
+    return false;
 
   return (!MEM_P (DECL_RTL (base)));
 }
 
-/* Returns true if the MEM_REF REF refers to an object that does not
+/* Returns true if REF refers to an object that does not
    reside in memory and has non-BLKmode.  */
 
 static inline bool
 mem_ref_refers_to_non_mem_p (tree ref)
 {
-  tree base = TREE_OPERAND (ref, 0);
-  return addr_expr_of_non_mem_decl_p_1 (base, false);
+  tree base;
+
+  if (TREE_CODE (ref) == MEM_REF
+      || TREE_CODE (ref) == TARGET_MEM_REF)
+    {
+      tree addr = TREE_OPERAND (ref, 0);
+
+      if (TREE_CODE (addr) != ADDR_EXPR)
+	return false;
+
+      base = TREE_OPERAND (addr, 0);
+    }
+  else
+    base = ref;
+
+  return non_mem_decl_p (base);
 }
 
 /* Expand an assignment that stores the value of FROM into TO.  If NONTEMPORAL
@@ -5004,7 +5013,7 @@ expand_assignment (tree to, tree from, bool nontem
        || TREE_CODE (to) == TARGET_MEM_REF
        || DECL_P (to))
       && mode != BLKmode
-      && (DECL_P (to) || !mem_ref_refers_to_non_mem_p (to))
+      && !mem_ref_refers_to_non_mem_p (to)
       && ((align = get_object_alignment (to))
 	  < GET_MODE_ALIGNMENT (mode))
       && (((icode = optab_handler (movmisalign_optab, mode))
Index: gcc/testsuite/g++.target/i386/pr91605.C
===================================================================
--- gcc/testsuite/g++.target/i386/pr91605.C	(revision 0)
+++ gcc/testsuite/g++.target/i386/pr91605.C	(working copy)
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-fpack-struct -mavx" } */
+
+struct A {
+  __attribute__((__vector_size__(4 * sizeof(double)))) double data;
+};
+struct B {
+  A operator*(B);
+};
+void fn1() {
+  B x, y;
+  x *y;
+}