From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 5 May 2017 15:43:22 +0000 (+0200)
Subject: re PR tree-optimization/80558 (VRP not handling x & -2 well)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ac699a047f74de2bb8f1d538b07c89075cd25c84;p=gcc.git

re PR tree-optimization/80558 (VRP not handling x & -2 well)

	PR tree-optimization/80558
	* tree-vrp.c (extract_range_from_binary_expr_1): Optimize
	[x, y] op z into [x op, y op z] for op & or | if conditions
	are met.

	* gcc.dg/tree-ssa/vrp115.c: New test.

From-SVN: r247641
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ff1d4996df1..51471bfc8fe 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2017-05-05  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/80558
+	* tree-vrp.c (extract_range_from_binary_expr_1): Optimize
+	[x, y] op z into [x op, y op z] for op & or | if conditions
+	are met.
+
 2017-05-05  Andre Vieira  <andre.simoesdiasvieira@arm.com>
 	    Prakhar Bahuguna  <prakhar.bahuguna@arm.com>
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8606518de58..7a1b00207ae 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-05-05  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/80558
+	* gcc.dg/tree-ssa/vrp115.c: New test.
+
 2017-05-05  Andre Vieira  <andre.simoesdiasvieira@arm.com>
 	    Thomas Preud'homme  <thomas.preudhomme@arm.com>
 	    Prakhar Bahuguna  <prakhar.bahuguna@arm.com>
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp115.c b/gcc/testsuite/gcc.dg/tree-ssa/vrp115.c
new file mode 100644
index 00000000000..6d1c9c50b37
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp115.c
@@ -0,0 +1,50 @@
+/* PR tree-optimization/80558 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-evrp" } */
+/* { dg-final { scan-tree-dump-not "link_error" "evrp" } } */
+
+void link_error (void);
+
+void
+f1 (int x)
+{
+  if (x >= 5 && x <= 19)
+    {
+      x &= -2;
+      if (x < 4 || x > 18)
+	link_error ();
+    }
+}
+
+void
+f2 (int x)
+{
+  if (x >= 5 && x <= 19)
+    {
+      x |= 7;
+      if (x < 7 || x > 23)
+	link_error ();
+    }
+}
+
+void
+f3 (int x)
+{
+  if (x >= -18 && x <= 19)
+    {
+      x |= 7;
+      if (x < -17 || x > 23)
+	link_error ();
+    }
+}
+
+void
+f4 (int x)
+{
+  if (x >= 1603 && x <= 2015)
+    {
+      x &= 496;
+      if (x < 64 || x > 464)
+	link_error ();
+    }
+}
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index cb1a3e59e79..cf50e908257 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -2865,8 +2865,59 @@ extract_range_from_binary_expr_1 (value_range *vr,
 						  &may_be_nonzero1,
 						  &must_be_nonzero1);
 
+      if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
+	{
+	  value_range *vr0p = NULL, *vr1p = NULL;
+	  if (range_int_cst_singleton_p (&vr1))
+	    {
+	      vr0p = &vr0;
+	      vr1p = &vr1;
+	    }
+	  else if (range_int_cst_singleton_p (&vr0))
+	    {
+	      vr0p = &vr1;
+	      vr1p = &vr0;
+	    }
+	  /* For op & or | attempt to optimize:
+	     [x, y] op z into [x op z, y op z]
+	     if z is a constant which (for op | its bitwise not) has n
+	     consecutive least significant bits cleared followed by m 1
+	     consecutive bits set immediately above it and either
+	     m + n == precision, or (x >> (m + n)) == (y >> (m + n)).
+	     The least significant n bits of all the values in the range are
+	     cleared or set, the m bits above it are preserved and any bits
+	     above these are required to be the same for all values in the
+	     range.  */
+	  if (vr0p && range_int_cst_p (vr0p))
+	    {
+	      wide_int w = vr1p->min;
+	      int m = 0, n = 0;
+	      if (code == BIT_IOR_EXPR)
+		w = ~w;
+	      if (wi::eq_p (w, 0))
+		n = TYPE_PRECISION (expr_type);
+	      else
+		{
+		  n = wi::ctz (w);
+		  w = ~(w | wi::mask (n, false, w.get_precision ()));
+		  if (wi::eq_p (w, 0))
+		    m = TYPE_PRECISION (expr_type) - n;
+		  else
+		    m = wi::ctz (w) - n;
+		}
+	      wide_int mask = wi::mask (m + n, true, w.get_precision ());
+	      if (wi::eq_p (mask & vr0p->min, mask & vr0p->max))
+		{
+		  min = int_const_binop (code, vr0p->min, vr1p->min);
+		  max = int_const_binop (code, vr0p->max, vr1p->min);
+		}
+	    }
+	}
+
       type = VR_RANGE;
-      if (code == BIT_AND_EXPR)
+      if (min && max)
+	/* Optimized above already.  */;
+      else if (code == BIT_AND_EXPR)
 	{
 	  min = wide_int_to_tree (expr_type,
 				  must_be_nonzero0 & must_be_nonzero1);