diff mbox series

tree-ssa-propagate: Special case lhs of musttail calls in may_propagate_copy [PR118430]

Message ID Z4eSh1gJXfSo3YtP@tucnak
State New
Headers
Series tree-ssa-propagate: Special case lhs of musttail calls in may_propagate_copy [PR118430] |

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Commit Message

Jakub Jelinek Jan. 15, 2025, 10:48 a.m. UTC 
  Hi!

And here is incremental (for now tested just on the new testcases)
patch to avoid VRP etc. to replace lhs of musttail call with something else.

2025-01-15  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/118430
	* tree-ssa-propagate.cc (may_propagate_copy): Return false if dest
	is lhs of an [[gnu::musttail]] call.
	(substitute_and_fold_dom_walker::before_dom_children): Formatting fix.

	* c-c++-common/musttail14.c: Expect lhs on the must tail call calls.


	Jakub

Comments

Richard Biener Jan. 15, 2025, 11:58 a.m. UTC | #1 
On Wed, 15 Jan 2025, Jakub Jelinek wrote:

> Hi!
> 
> And here is incremental (for now tested just on the new testcases)
> patch to avoid VRP etc. to replace lhs of musttail call with something else.

OK.

Thanks,
Richard.

> 2025-01-15  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR tree-optimization/118430
> 	* tree-ssa-propagate.cc (may_propagate_copy): Return false if dest
> 	is lhs of an [[gnu::musttail]] call.
> 	(substitute_and_fold_dom_walker::before_dom_children): Formatting fix.
> 
> 	* c-c++-common/musttail14.c: Expect lhs on the must tail call calls.
> 
> --- gcc/tree-ssa-propagate.cc.jj	2025-01-02 11:23:02.000000000 +0100
> +++ gcc/tree-ssa-propagate.cc	2025-01-15 11:34:38.554602529 +0100
> @@ -870,7 +870,7 @@ substitute_and_fold_dom_walker::before_d
>  	}
>        /* Also fold if we want to fold all statements.  */
>        else if (substitute_and_fold_engine->fold_all_stmts
> -	  && fold_stmt (&i, follow_single_use_edges))
> +	       && fold_stmt (&i, follow_single_use_edges))
>  	{
>  	  did_replace = true;
>  	  stmt = gsi_stmt (i);
> @@ -1081,6 +1081,13 @@ may_propagate_copy (tree dest, tree orig
>    if (TREE_CODE (dest) == SSA_NAME && virtual_operand_p (dest))
>      return false;
>  
> +  /* Keep lhs of [[gnu::musttail]] calls as is, those need to be still
> +     tail callable.  */
> +  if (TREE_CODE (dest) == SSA_NAME
> +      && is_gimple_call (SSA_NAME_DEF_STMT (dest))
> +      && gimple_call_must_tail_p (as_a <gcall *> (SSA_NAME_DEF_STMT (dest))))
> +    return false;
> +
>    /* Anything else is OK.  */
>    return true;
>  }
> --- gcc/testsuite/c-c++-common/musttail14.c.jj	2025-01-15 11:32:58.048016223 +0100
> +++ gcc/testsuite/c-c++-common/musttail14.c	2025-01-15 11:33:30.982552975 +0100
> @@ -1,9 +1,9 @@
>  /* PR tree-optimization/118430 */
>  /* { dg-do compile { target musttail } } */
>  /* { dg-options "-O2 -fdump-tree-optimized" } */
> -/* { dg-final { scan-tree-dump-times "  bar \\\(\[^\n\r]\*\\\); \\\[tail call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
> -/* { dg-final { scan-tree-dump-times "  freddy \\\(\[^\n\r]\*\\\); \\\[tail call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
> -/* { dg-final { scan-tree-dump-times "  (?:bar|freddy) \\\(\[^\n\r]\*\\\); \\\[tail call\\\]" 2 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "  \[^\n\r]* = bar \\\(\[^\n\r]\*\\\); \\\[tail call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "  \[^\n\r]* = freddy \\\(\[^\n\r]\*\\\); \\\[tail call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
> +/* { dg-final { scan-tree-dump-not "  (?:bar|freddy) \\\(\[^\n\r]\*\\\); \\\[tail call\\\]" "optimized" } } */
>  
>  __attribute__ ((noipa)) void
>  foo (int x)
> 
> 	Jakub
> 
>
diff mbox series

Patch

--- gcc/tree-ssa-propagate.cc.jj	2025-01-02 11:23:02.000000000 +0100
+++ gcc/tree-ssa-propagate.cc	2025-01-15 11:34:38.554602529 +0100
@@ -870,7 +870,7 @@  substitute_and_fold_dom_walker::before_d
 	}
       /* Also fold if we want to fold all statements.  */
       else if (substitute_and_fold_engine->fold_all_stmts
-	  && fold_stmt (&i, follow_single_use_edges))
+	       && fold_stmt (&i, follow_single_use_edges))
 	{
 	  did_replace = true;
 	  stmt = gsi_stmt (i);
@@ -1081,6 +1081,13 @@  may_propagate_copy (tree dest, tree orig
   if (TREE_CODE (dest) == SSA_NAME && virtual_operand_p (dest))
     return false;
 
+  /* Keep lhs of [[gnu::musttail]] calls as is, those need to be still
+     tail callable.  */
+  if (TREE_CODE (dest) == SSA_NAME
+      && is_gimple_call (SSA_NAME_DEF_STMT (dest))
+      && gimple_call_must_tail_p (as_a <gcall *> (SSA_NAME_DEF_STMT (dest))))
+    return false;
+
   /* Anything else is OK.  */
   return true;
 }
--- gcc/testsuite/c-c++-common/musttail14.c.jj	2025-01-15 11:32:58.048016223 +0100
+++ gcc/testsuite/c-c++-common/musttail14.c	2025-01-15 11:33:30.982552975 +0100
@@ -1,9 +1,9 @@ 
 /* PR tree-optimization/118430 */
 /* { dg-do compile { target musttail } } */
 /* { dg-options "-O2 -fdump-tree-optimized" } */
-/* { dg-final { scan-tree-dump-times "  bar \\\(\[^\n\r]\*\\\); \\\[tail call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
-/* { dg-final { scan-tree-dump-times "  freddy \\\(\[^\n\r]\*\\\); \\\[tail call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
-/* { dg-final { scan-tree-dump-times "  (?:bar|freddy) \\\(\[^\n\r]\*\\\); \\\[tail call\\\]" 2 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "  \[^\n\r]* = bar \\\(\[^\n\r]\*\\\); \\\[tail call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "  \[^\n\r]* = freddy \\\(\[^\n\r]\*\\\); \\\[tail call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-not "  (?:bar|freddy) \\\(\[^\n\r]\*\\\); \\\[tail call\\\]" "optimized" } } */
 
 __attribute__ ((noipa)) void
 foo (int x)