From 8fa40c65f417914ac74fbc44243671d13d85b9f3 Mon Sep 17 00:00:00 2001
From: Martin Sebor <msebor@redhat.com>
Date: Fri, 14 Aug 2020 17:11:53 -0600
Subject: PR tree-optimization/78257 - missing memcmp optimization with
 constant arrays

gcc/ChangeLog:

	PR middle-end/78257
	* builtins.c (expand_builtin_memory_copy_args): Rename called function.
	(expand_builtin_stpcpy_1): Remove argument from call.
	(expand_builtin_memcmp): Rename called function.
	(inline_expand_builtin_bytecmp): Same.
	* expr.c (convert_to_bytes): New function.
	(constant_byte_string): New function (formerly string_constant).
	(string_constant): Call constant_byte_string.
	(byte_representation): New function.
	* expr.h (byte_representation): Declare.
	* fold-const-call.c (fold_const_call): Rename called function.
	* fold-const.c (c_getstr): Remove an argument.
	(getbyterep): Define a new function.
	* fold-const.h (c_getstr): Remove an argument.
	(getbyterep): Declare a new function.
	* gimple-fold.c (gimple_fold_builtin_memory_op): Rename callee.
	(gimple_fold_builtin_string_compare): Same.
	(gimple_fold_builtin_memchr): Same.

gcc/testsuite/ChangeLog:

	PR middle-end/78257
	* gcc.dg/memchr.c: New test.
	* gcc.dg/memcmp-2.c: New test.
	* gcc.dg/memcmp-3.c: New test.
	* gcc.dg/memcmp-4.c: New test.
---
 gcc/testsuite/gcc.dg/memchr.c | 94 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/memchr.c

(limited to 'gcc/testsuite/gcc.dg/memchr.c')

diff --git a/gcc/testsuite/gcc.dg/memchr.c b/gcc/testsuite/gcc.dg/memchr.c
new file mode 100644
index 0000000..fb21d58
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/memchr.c
@@ -0,0 +1,94 @@
+/* PR middle-end/78257 - missing memcmp optimization with constant arrays
+   { dg-do compile }
+   { dg-options "-O -Wall -fdump-tree-optimized" } */
+
+typedef __INT8_TYPE__  int8_t;
+typedef __INT16_TYPE__ int16_t;
+typedef __INT32_TYPE__ int32_t;
+typedef __SIZE_TYPE__  size_t;
+
+extern void* memchr (const void*, int, size_t);
+
+/* Verify that initializers for flexible array members are handled
+   correctly.  */
+
+struct SX
+{
+  /* offset */
+  /*   0    */ int32_t n;
+  /*   4    */ int8_t: 1;
+  /*   6    */ int16_t a[];
+};
+
+_Static_assert (__builtin_offsetof (struct SX, a) == 6);
+
+const struct SX sx =
+  {
+   0x11121314, { 0x2122, 0x3132, 0x4142, 0x5152 }
+  };
+
+const char sx_rep[] =
+  {
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+   0x11, 0x12, 0x13, 0x14, 0, 0, 0x21, 0x22, 0x31, 0x32, 0x41, 0x42, 0x51, 0x52
+#else
+   0x14, 0x13, 0x12, 0x11, 0, 0, 0x22, 0x21, 0x32, 0x31, 0x42, 0x41, 0x52, 0x51
+#endif
+  };
+
+
+void test_find (void)
+{
+  int n = 0, nb = (const char*)&sx.a[4] - (const char*)&sx;
+  const char *p = (const char*)&sx, *q = sx_rep;
+
+  if (nb != sizeof sx_rep)
+    __builtin_abort ();
+
+  n += p      == memchr (p, q[ 0], nb);
+  n += p +  1 == memchr (p, q[ 1], nb);
+  n += p +  2 == memchr (p, q[ 2], nb);
+  n += p +  3 == memchr (p, q[ 3], nb);
+  n += p +  4 == memchr (p, q[ 4], nb);
+  n += p +  4 == memchr (p, q[ 5], nb);
+  n += p +  6 == memchr (p, q[ 6], nb);
+  n += p +  7 == memchr (p, q[ 7], nb);
+  n += p +  8 == memchr (p, q[ 8], nb);
+  n += p +  9 == memchr (p, q[ 9], nb);
+  n += p + 10 == memchr (p, q[10], nb);
+  n += p + 11 == memchr (p, q[11], nb);
+  n += p + 12 == memchr (p, q[12], nb);
+  n += p + 13 == memchr (p, q[13], nb);
+
+  if (n != 14)
+    __builtin_abort ();
+}
+
+void test_not_find (void)
+{
+  int n = 0, nb = (const char*)&sx.a[4] - (const char*)&sx;
+  const char *p = (const char*)&sx, *q = sx_rep;
+
+  if (nb != sizeof sx_rep)
+    __builtin_abort ();
+
+  n += 0 == memchr (p,      0xff, nb);
+  n += 0 == memchr (p +  1, q[ 0], nb - 1);
+  n += 0 == memchr (p +  2, q[ 1], nb - 2);
+  n += 0 == memchr (p +  3, q[ 2], nb - 3);
+  n += 0 == memchr (p +  4, q[ 3], nb - 4);
+  n += 0 == memchr (p +  6, q[ 4], nb - 6);
+  n += 0 == memchr (p +  7, q[ 6], nb - 7);
+  n += 0 == memchr (p +  8, q[ 7], nb - 8);
+  n += 0 == memchr (p +  9, q[ 8], nb - 9);
+  n += 0 == memchr (p + 10, q[ 9], nb - 10);
+  n += 0 == memchr (p + 11, q[10], nb - 11);
+  n += 0 == memchr (p + 12, q[11], nb - 12);
+  n += 0 == memchr (p + 13, q[12], nb - 13);
+  n += 0 == memchr (p + 14, q[13], nb - 14);
+
+  if (n != 14)
+    __builtin_abort ();
+}
+
+/* { dg-final { scan-tree-dump-not "abort" "optimized" } } */
-- 
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