From f26916c2acdda19e36e57fff97b296897ebcba76 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 7 Jan 2020 11:03:07 +0100
Subject: [PATCH] re PR tree-optimization/93118 (>>32<<32 is not always
 converted into &~0ffffffffull at the tree level)

	PR tree-optimization/93118
	* match.pd ((x >> c) << c -> x & (-1<<c)): Add nop_convert?.  Add new
	simplifier with two intermediate conversions.

	* gcc.dg/tree-ssa/pr93118.c: New test.

From-SVN: r279950
---
 gcc/ChangeLog                           |  6 ++++
 gcc/match.pd                            | 21 ++++++++++--
 gcc/testsuite/ChangeLog                 |  5 +++
 gcc/testsuite/gcc.dg/tree-ssa/pr93118.c | 45 +++++++++++++++++++++++++
 4 files changed, 75 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr93118.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 568076bd673..f90dc081d04 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-01-07  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/93118
+	* match.pd ((x >> c) << c -> x & (-1<<c)): Add nop_convert?.  Add new
+	simplifier with two intermediate conversions.
+
 2020-01-07  Martin Liska  <mliska@suse.cz>
 
 	* params.opt: Add Optimization for various parameters.
diff --git a/gcc/match.pd b/gcc/match.pd
index fac1dfc13a9..a3badb2c44b 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2738,9 +2738,26 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 
 /* Optimize (x >> c) << c into x & (-1<<c).  */
 (simplify
- (lshift (rshift @0 INTEGER_CST@1) @1)
+ (lshift (nop_convert? (rshift @0 INTEGER_CST@1)) @1)
  (if (wi::ltu_p (wi::to_wide (@1), element_precision (type)))
-  (bit_and @0 (lshift { build_minus_one_cst (type); } @1))))
+  /* It doesn't matter if the right shift is arithmetic or logical.  */
+  (bit_and (view_convert @0) (lshift { build_minus_one_cst (type); } @1))))
+
+(simplify
+ (lshift (convert (convert@2 (rshift @0 INTEGER_CST@1))) @1)
+ (if (wi::ltu_p (wi::to_wide (@1), element_precision (type))
+      /* Allow intermediate conversion to integral type with whatever sign, as
+	 long as the low TYPE_PRECISION (type)
+	 - TYPE_PRECISION (TREE_TYPE (@2)) bits are preserved.  */
+      && INTEGRAL_TYPE_P (type)
+      && INTEGRAL_TYPE_P (TREE_TYPE (@2))
+      && INTEGRAL_TYPE_P (TREE_TYPE (@0))
+      && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (@0))
+      && (TYPE_PRECISION (TREE_TYPE (@2)) >= TYPE_PRECISION (type)
+	  || wi::geu_p (wi::to_wide (@1),
+			TYPE_PRECISION (type)
+			- TYPE_PRECISION (TREE_TYPE (@2)))))
+  (bit_and (convert @0) (lshift { build_minus_one_cst (type); } @1))))
 
 /* Optimize (x << c) >> c into x & ((unsigned)-1 >> c) for unsigned
    types.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4e02fb48c3b..403bc8a05f5 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-01-07  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/93118
+	* gcc.dg/tree-ssa/pr93118.c: New test.
+
 2020-01-07  Martin Liska  <mliska@suse.cz>
 
 	PR tree-optimization/92860
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr93118.c b/gcc/testsuite/gcc.dg/tree-ssa/pr93118.c
new file mode 100644
index 00000000000..92e9310bf6b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr93118.c
@@ -0,0 +1,45 @@
+/* PR tree-optimization/93118 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-not ">>" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "<<" "optimized" } } */
+
+#if __SIZEOF_LONG_LONG__ == 8 && __SIZEOF_INT__ == 4 && __CHAR_BIT__ == 8
+unsigned long long
+foo (unsigned long long a)
+{
+  unsigned long long b = a >> 32;
+  int c = b;
+  unsigned long long d = c;
+  return d << 32;
+}
+
+unsigned long long
+bar (unsigned long long a)
+{
+  unsigned long long b = a >> 32;
+  unsigned c = b;
+  unsigned long long d = c;
+  return d << 32;
+}
+
+unsigned long long
+baz (long long a)
+{
+  long long b = a >> 32;
+  unsigned long long c = b;
+  return c << 32;
+}
+
+typedef unsigned V __attribute__((vector_size (2 * sizeof (int))));
+typedef int W __attribute__((vector_size (2 * sizeof (int))));
+
+void
+quux (W *w, V *v)
+{
+  W a = (W) (*v >> 16);
+  *w = a << 16;
+}
+#else
+int i;
+#endif
-- 
2.30.2