PR middle-end/29749

	* fold-const.c (fold_binary) <case BIT_AND_EXPR>: Optimize
	(X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
	and (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1)).
	(fold_binary) <case LSHIFT_EXPR, case RSHIFT_EXPR>: Optimize
	(X & C2) << C1 into (X << C1) & (C2 << C1) and
	(X & C2) >> C1 into (X >> C1) & (C2 >> C1) if that allows further
	optimizations.

	* gcc.dg/fold-rotate-1.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@130589 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 74 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/fold-rotate-1.c b/gcc/testsuite/gcc.dg/fold-rotate-1.c
new file mode 100644
index 00000000000..c04447fb3cf
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-rotate-1.c
@@ -0,0 +1,74 @@
+/* PR middle-end/29749 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+
+#if __SCHAR_MAX__ == 127
+
+unsigned char
+e1 (unsigned char a)
+{
+  return a >> 5 | a << 3;
+}
+
+unsigned char
+e2 (unsigned char a)
+{
+  return (a & 0xe0) >> 5 | (a & 0x1f) << 3;
+}
+
+unsigned char
+e3 (unsigned char a)
+{
+  return ((a >> 5) & 0x07) | ((a << 3) & 0xf8);
+}
+
+#endif
+
+#if __SHRT_MAX__ == 32767
+
+unsigned short
+f1 (unsigned short a)
+{
+  return a >> 8 | a << 8;
+}
+
+unsigned short
+f2 (unsigned short a)
+{
+  return (a & 0xff00) >> 8 | (a & 0x00ff) << 8;
+}
+
+unsigned short
+f3 (unsigned short a)
+{
+  return ((a >> 8) & 0x00ff) | ((a << 8) & 0xff00);
+}
+
+#endif
+
+#if __INT_MAX__ == 2147483647
+
+unsigned int
+g1 (unsigned int a)
+{
+  return a >> 24 | a << 8;
+}
+
+unsigned int
+g2 (unsigned int a)
+{
+  return (a & 0xff000000) >> 24 | (a & 0x00ffffff) << 8;
+}
+
+unsigned int
+g3 (unsigned int a)
+{
+  return ((a >> 24) & 0x000000ff) | ((a << 8) & 0xffffff00U);
+}
+
+#endif
+
+int i;
+
+/* { dg-final { scan-tree-dump-times "&" 0 "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */