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Relax boolean processing in vect_maybe_update_slp_op_vectype

Message ID 20241017130351.B5E4C3858420@sourceware.org
State New
Headers show
Series Relax boolean processing in vect_maybe_update_slp_op_vectype | expand

Commit Message

Richard Biener Oct. 17, 2024, 1:03 p.m. UTC 
The following makes VECTOR_BOOLEAN_TYPE_P processing consistent with
what we do without SLP.  The original motivation for rejecting of
VECTOR_BOOLEAN_TYPE_P extern defs was bad code generation.  But
the non-SLP codepath happily goes along - but always hits the
case of an uniform vector and this case specifically we can now
code-generate optimally.  So the following allows single-lane
externs as well.

Requiring patterns to code-generate can have bad influence on
the vectorization factor though a prototype patch of mine shows
that generating vector compares externally isn't always trivial.

The patch fixes the gcc.dg/vect/vect-early-break_82.c FAIL on x86_64
when --param vect-force-slp=1 is in effect.

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

	PR tree-optimization/117171
	* tree-vect-stmts.cc (vect_maybe_update_slp_op_vectype):
	Relax vect_external_def VECTOR_BOOLEAN_TYPE_P constraint.
---
 gcc/tree-vect-stmts.cc | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
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Patch

diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 948726d51c5..7d7d1512bd4 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -14292,9 +14292,12 @@  vect_maybe_update_slp_op_vectype (slp_tree op, tree vectype)
   if (SLP_TREE_VECTYPE (op))
     return types_compatible_p (SLP_TREE_VECTYPE (op), vectype);
   /* For external defs refuse to produce VECTOR_BOOLEAN_TYPE_P, those
-     should be handled by patters.  Allow vect_constant_def for now.  */
+     should be handled by patters.  Allow vect_constant_def for now
+     as well as the trivial single-lane uniform vect_external_def case
+     both of which we code-generate reasonably.  */
   if (VECTOR_BOOLEAN_TYPE_P (vectype)
-      && SLP_TREE_DEF_TYPE (op) == vect_external_def)
+      && SLP_TREE_DEF_TYPE (op) == vect_external_def
+      && SLP_TREE_LANES (op) > 1)
     return false;
   SLP_TREE_VECTYPE (op) = vectype;
   return true;