store-merging: Allow enums during bswap recognition [PR94403]

The following testcase is optimized with char/unsigned char/signed char,
but not with std::byte.  The following patch fixes that.  Didn't use
INTEGRAL_TYPE_P because bswapping bools is just too weird.

2020-03-31  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/94403
	* gimple-ssa-store-merging.c (verify_symbolic_number_p): Allow also
	ENUMERAL_TYPE lhs_type.

	* g++.dg/tree-ssa/pr94403.C: New test.

gcc/ChangeLog

 2020-03-31  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/94403
+	* gimple-ssa-store-merging.c (verify_symbolic_number_p): Allow also
+	ENUMERAL_TYPE lhs_type.
+
 	PR rtl-optimization/94344
 	* tree-ssa-forwprop.c (simplify_rotate): Handle also same precision
 	conversions, either on both operands of |^+ or just one.  Handle

gcc/gimple-ssa-store-merging.c

@@ -315,7 +315,8 @@ verify_symbolic_number_p (struct symbolic_number *n, gimple *stmt)
 
   lhs_type = gimple_expr_type (stmt);
 
-  if (TREE_CODE (lhs_type) != INTEGER_TYPE)
+  if (TREE_CODE (lhs_type) != INTEGER_TYPE
+      && TREE_CODE (lhs_type) != ENUMERAL_TYPE)
     return false;
 
   if (TYPE_PRECISION (lhs_type) != TYPE_PRECISION (n->type))

gcc/testsuite/ChangeLog

 2020-03-31  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/94403
+	* g++.dg/tree-ssa/pr94403.C: New test.
+
 	PR rtl-optimization/94344
 	* gcc.dg/pr94344.c: New test.
 

gcc/testsuite/g++.dg/tree-ssa/pr94403.C

+// PR tree-optimization/94403
+// Only test on some 64-bit targets which do have bswap{si,di}2 patterns and
+// are either big or little endian (not pdp endian).
+// { dg-do compile { target { lp64 && { i?86-*-* x86_64-*-* powerpc*-*-* aarch64*-*-* } } } }
+// { dg-require-effective-target store_merge }
+// { dg-options "-O2 -fdump-tree-store-merging -std=c++17" }
+
+namespace std {
+  template <typename T>
+  void swap (T& t1, T& t2) { T tmp (t1); t1 = t2; t2 = tmp; }
+  enum class byte : unsigned char {};
+}
+
+unsigned
+bswap32 (unsigned int x)
+{
+  unsigned int y = x;
+  std::byte *bytes = reinterpret_cast<std::byte*> (&y);
+  std::swap (bytes[0], bytes[3]);
+  std::swap (bytes[1], bytes[2]);
+  return y;
+}
+
+unsigned long long
+bswap64 (unsigned long long x)
+{
+  unsigned long long y = x;
+  std::byte *bytes = reinterpret_cast<std::byte*> (&y);
+  std::swap (bytes[0], bytes[7]);
+  std::swap (bytes[1], bytes[6]);
+  std::swap (bytes[2], bytes[5]);
+  std::swap (bytes[3], bytes[4]);
+  return y;
+}
+
+/* { dg-final { scan-tree-dump-times "__builtin_bswap64" 1 "store-merging" } } */
+/* { dg-final { scan-tree-dump-times "__builtin_bswap32" 1 "store-merging" } } */