From: Richard Biener <rguenther@suse.de>
Date: Wed, 23 Sep 2020 13:03:31 +0000 (+0200)
Subject: middle-end/96453 - relax gimple_expand_vec_cond_expr
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=3457dae55f72bd4ac0f346bbebb02d1613ac4b5c;p=gcc.git

middle-end/96453 - relax gimple_expand_vec_cond_expr

This relaxes the condition under which we also try NE_EXPR
for a fake generated compare in addition to LT_EXPR given
the fact the verification ICEd when it failed but obviously
was only implemented for constants.  Thus the patch removes
the verification and the restriction to constant operands.

2020-09-23  Richard Biener  <rguenther@suse.de>

	PR middle-end/96453
	* gimple-isel.cc (gimple_expand_vec_cond_expr): Remove
	LT_EXPR -> NE_EXPR verification and also apply it for
	non-constant masks.

	* gcc.dg/pr96453.c: New testcase.
---

diff --git a/gcc/gimple-isel.cc b/gcc/gimple-isel.cc
index b330cf4c20e..97922632afd 100644
--- a/gcc/gimple-isel.cc
+++ b/gcc/gimple-isel.cc
@@ -138,22 +138,11 @@ gimple_expand_vec_cond_expr (gimple_stmt_iterator *gsi,
   if (icode == CODE_FOR_nothing)
     {
       if (tcode == LT_EXPR
-	  && op0a == op0
-	  && TREE_CODE (op0) == VECTOR_CST)
+	  && op0a == op0)
 	{
 	  /* A VEC_COND_EXPR condition could be folded from EQ_EXPR/NE_EXPR
 	     into a constant when only get_vcond_eq_icode is supported.
-	     Verify < 0 and != 0 behave the same and change it to NE_EXPR.  */
-	  unsigned HOST_WIDE_INT nelts;
-	  if (!VECTOR_CST_NELTS (op0).is_constant (&nelts))
-	    {
-	      if (VECTOR_CST_STEPPED_P (op0))
-		gcc_unreachable ();
-	      nelts = vector_cst_encoded_nelts (op0);
-	    }
-	  for (unsigned int i = 0; i < nelts; ++i)
-	    if (tree_int_cst_sgn (vector_cst_elt (op0, i)) == 1)
-	      gcc_unreachable ();
+	     Try changing it to NE_EXPR.  */
 	  tcode = NE_EXPR;
 	}
       if (tcode == EQ_EXPR || tcode == NE_EXPR)
diff --git a/gcc/testsuite/gcc.dg/pr96453.c b/gcc/testsuite/gcc.dg/pr96453.c
new file mode 100644
index 00000000000..f758e7ec77a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr96453.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-Og -fno-early-inlining -fno-tree-ccp -fno-tree-dce" } */
+/* { dg-additional-options "-mavx -mno-sse4.2" { target x86_64-*-* i?86-*-* } } */
+
+typedef int __attribute__ ((__vector_size__ (16))) U;
+typedef unsigned long __attribute__ ((__vector_size__ (16))) V;
+
+static inline int
+bar (unsigned long e, V f)
+{
+  V g = f != e;
+  (union {U b;}){(U) g};
+}
+
+void
+foo (void)
+{
+  int j = bar (8, (V) { });
+  for (unsigned i;; i[&j])
+    ;
+}