It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/autoconf/m4/flex.m4 b/autoconf/m4/flex.m4
new file mode 100644
index 0000000..5cb3dc4
--- /dev/null
+++ b/autoconf/m4/flex.m4
@@ -0,0 +1,17 @@
+#
+# Check for FLEX.  
+#
+# This macro verifies that flex is installed.  If successful, then
+# 1) $LEX is set to "flex" (to emulate lex calls)
+# 2) BISON is set to bison
+AC_DEFUN([AC_PROG_FLEX],
+[AC_CACHE_CHECK(,
+ac_cv_has_flex,
+[AC_PROG_LEX()
+])
+if test "$LEX" != "flex"; then
+  AC_MSG_ERROR([flex not found but required])
+else
+  AC_SUBST(FLEX,[flex],[location of flex])
+fi
+])