Simplify memchr with small constant strings

When memchr is applied on a constant string of no more than the bytes of
a word, simplify memchr by checking each byte in the constant string.

int f (int a)
{
   return  __builtin_memchr ("AE", a, 2) != 0;
}

is simplified to

int f (int a)
{
  return ((char) a == 'A' || (char) a == 'E') != 0;
}

gcc/

	PR tree-optimization/103798
	* tree-ssa-forwprop.cc: Include "tree-ssa-strlen.h".
	(simplify_builtin_call): Inline memchr with constant strings of
	no more than the bytes of a word.
	* tree-ssa-strlen.cc (use_in_zero_equality): Make it global.
	* tree-ssa-strlen.h (use_in_zero_equality): New.

gcc/testsuite/

	PR tree-optimization/103798
	* c-c++-common/pr103798-1.c: New test.
	* c-c++-common/pr103798-2.c: Likewise.
	* c-c++-common/pr103798-3.c: Likewise.
	* c-c++-common/pr103798-4.c: Likewise.
	* c-c++-common/pr103798-5.c: Likewise.
	* c-c++-common/pr103798-6.c: Likewise.
	* c-c++-common/pr103798-7.c: Likewise.
	* c-c++-common/pr103798-8.c: Likewise.
	* c-c++-common/pr103798-9.c: Likewise.
	* c-c++-common/pr103798-10.c: Likewise.

10 files changed, 241 insertions, 0 deletions

diff --git a/gcc/testsuite/c-c++-common/pr103798-1.c b/gcc/testsuite/c-c++-common/pr103798-1.c
new file mode 100644
index 0000000..cd3edf5
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-1.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int
+f (char a)
+{
+   return  __builtin_memchr ("a", a, 1) == 0;
+}
+
+__attribute__ ((weak))
+int
+g (char a)
+{
+  return a != 'a';
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+   if (f (i) != g (i))
+     __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-10.c b/gcc/testsuite/c-c++-common/pr103798-10.c
new file mode 100644
index 0000000..4677e95
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-10.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-Os -fdump-tree-optimized -save-temps" } */
+
+int
+f (char a)
+{
+  return  __builtin_memchr ("ac", a, 1) == 0;
+}
+
+/* { dg-final { scan-assembler "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-2.c b/gcc/testsuite/c-c++-common/pr103798-2.c
new file mode 100644
index 0000000..e7e99c3
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-2.c
@@ -0,0 +1,30 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+#include <string.h>
+
+__attribute__ ((weak))
+int
+f (int a)
+{
+   return memchr ("aE", a, 2) != NULL;
+}
+
+__attribute__ ((weak))
+int
+g (char a)
+{
+  return a == 'a' || a == 'E';
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+   if (f (i + 256) != g (i + 256))
+     __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-3.c b/gcc/testsuite/c-c++-common/pr103798-3.c
new file mode 100644
index 0000000..ddcedc7
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-3.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int
+f (char a)
+{
+   return  __builtin_memchr ("aEgZ", a, 3) == 0;
+}
+
+__attribute__ ((weak))
+int
+g (char a)
+{
+  return a != 'a' && a != 'E' && a != 'g';
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+   if (f (i) != g (i))
+     __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-4.c b/gcc/testsuite/c-c++-common/pr103798-4.c
new file mode 100644
index 0000000..00e8302
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-4.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int
+f (char a)
+{
+   return  __builtin_memchr ("aEgi", a, 4) != 0;
+}
+
+__attribute__ ((weak))
+int
+g (char a)
+{
+  return a == 'a' || a == 'E' || a == 'g' || a == 'i';
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+   if (f (i) != g (i))
+     __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-5.c b/gcc/testsuite/c-c++-common/pr103798-5.c
new file mode 100644
index 0000000..0d6487a
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-5.c
@@ -0,0 +1,26 @@
+/* { dg-do run { target int128 } } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int f(char a)
+{
+   return  __builtin_memchr ("aEgiH", a, 5) == 0;
+}
+
+__attribute__ ((weak))
+int g(char a)
+{
+  return a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H';
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+   if (f (i) != g (i))
+     __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-6.c b/gcc/testsuite/c-c++-common/pr103798-6.c
new file mode 100644
index 0000000..5ccb5ee
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-6.c
@@ -0,0 +1,27 @@
+/* { dg-do run { target int128 } } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int f(char a)
+{
+   return  __builtin_memchr ("aEgiHx", a, 6) != 0;
+}
+
+__attribute__ ((weak))
+int g(char a)
+{
+  return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
+	  || a == 'x');
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+   if (f (i) != g (i))
+     __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-7.c b/gcc/testsuite/c-c++-common/pr103798-7.c
new file mode 100644
index 0000000..40fd382
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-7.c
@@ -0,0 +1,27 @@
+/* { dg-do run { target int128 } } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int f(char a)
+{
+   return  __builtin_memchr ("aEgiHjZ", a, 7) == 0;
+}
+
+__attribute__ ((weak))
+int g(char a)
+{
+  return (a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H'
+	  && a != 'j' && a != 'Z');
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+   if (f (i) != g (i))
+     __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-8.c b/gcc/testsuite/c-c++-common/pr103798-8.c
new file mode 100644
index 0000000..0841b18
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-8.c
@@ -0,0 +1,27 @@
+/* { dg-do run { target int128 } } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int f(int a)
+{
+   return  __builtin_memchr ("aEgiHx19ABC", a, 8) != 0;
+}
+
+__attribute__ ((weak))
+int g(char a)
+{
+  return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
+	  || a == 'x' || a == '1' || a == '9');
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+   if (f (i + 256) != g (i + 256))
+     __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-9.c b/gcc/testsuite/c-c++-common/pr103798-9.c
new file mode 100644
index 0000000..c5f0f94
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-9.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-Os -fdump-tree-optimized -save-temps" } */
+
+int
+f (char a)
+{
+  return  __builtin_memchr ("a", a, 1) == 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */