[PATCH] tree-optimization/103489 - fix ICE when bool pattern recog fails

Richard Biener rguenther@suse.de
Tue Nov 30 14:01:12 GMT 2021


bool pattern recog currently does not handle cycles correctly
and when it fails we can ICE later vectorizing PHIs with
mismatched bool and non-bool vector types.  The following avoids
blindly trusting bool pattern recog here and verifies things
more thoroughly in vectorizable_phi.  A bool pattern recog fix
is for GCC 13.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

2021-11-30  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/103489
	* tree-vect-loop.c (vectorizable_phi): Verify argument
	vector type compatibility to mitigate bool pattern recog
	bug.

	* gcc.dg/torture/pr103489.c: New testcase.
---
 gcc/testsuite/gcc.dg/torture/pr103489.c | 12 ++++++++++++
 gcc/tree-vect-loop.c                    | 18 ++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/torture/pr103489.c

diff --git a/gcc/testsuite/gcc.dg/torture/pr103489.c b/gcc/testsuite/gcc.dg/torture/pr103489.c
new file mode 100644
index 00000000000..cd62623ece2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr103489.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-ftree-vectorize" } */
+
+_Bool a[80];
+short b, f;
+void g(short h[][8][16])
+{
+  for (_Bool c = 0; c < b;)
+    for (_Bool d = 0; d < (_Bool)f; d = 1)
+      for (short e = 0; e < 16; e++)
+        a[e] = h[b][1][e];
+}
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 841da78f1fd..7f544ba1fd5 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -7846,6 +7846,24 @@ vectorizable_phi (vec_info *,
 			       "incompatible vector types for invariants\n");
 	    return false;
 	  }
+	else if (SLP_TREE_DEF_TYPE (child) == vect_internal_def
+		 && !useless_type_conversion_p (vectype,
+						SLP_TREE_VECTYPE (child)))
+	  {
+	    /* With bools we can have mask and non-mask precision vectors,
+	       while pattern recog is supposed to guarantee consistency here
+	       bugs in it can cause mismatches (PR103489 for example).
+	       Deal with them here instead of ICEing later.  */
+	    if (dump_enabled_p ())
+	      dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+			       "incompatible vector type setup from "
+			       "bool pattern detection\n");
+	    gcc_checking_assert
+	      (VECTOR_BOOLEAN_TYPE_P (SLP_TREE_VECTYPE (child))
+	       != VECTOR_BOOLEAN_TYPE_P (vectype));
+	    return false;
+	  }
+
       /* For single-argument PHIs assume coalescing which means zero cost
 	 for the scalar and the vector PHIs.  This avoids artificially
 	 favoring the vector path (but may pessimize it in some cases).  */
-- 
2.31.1


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